community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Eugeny S. Mints]

Pavel,

Pavel Machek wrote:
 >
[snip]
 >> Are you arguing that the cpufreq interface be morphed to support power
 >> op applications?
 >
 > No. I'm arguing that
 >
 > * cpufreq interface should be used for changing cpu frequency
the patch set i sent out has cpufreq used for changing cpu frequency,
hasn't it?
 > * additional interfaces should be created for changing memory clock
 > etc.
the patch set I sent out allows to extend cpufreq interface to control
memory clock, etc by building all necessary additional pieces on top of
PowerOP Core layer which in conjunction with PM Core and clock/voltage
framework layers provides PM stack with well defined loosely coupled
interfaces between layers and PM functionality logically spread across
the layers instead if having everything mixed in one piece as cpufreq
does.
 > * existing interfaces should be used for turning devices on/off (and
 > new ones created when old ones do not exist)
PowerOP patch set for now is presenting just main basic block but
integration with devices suspend/resume, constraints, etc is next steps.
For now exactly existing interfaces for turning devices on/off may be used
in conjunction with poweop patch set although the interfaces may be
improved in the future if necessary
 > * powerop should take a look what userspace wants, and just close
 > closest point to that.
PowerOP is interface which allows wide range of interfaces to be built on
top of it including the interface you mentioned here. PowerOP/cpufreq
integration patch demonstrates this.

can we eventually start talking more close to the code rather than
speculating without it?

Pavel, if you feel that comments I put here don't correspond
to what my code is doing please show this by commenting the patch set
code.

Thanks,
	Eugeny
 > 							Pavel
 >

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Pavel Machek]

Hi!

On Mon 2006-09-11 11:57:28, Eugeny S. Mints wrote:
> [snip]
> >> Are you arguing that the cpufreq interface be morphed to support power
> >> op applications?
> >
> > No. I'm arguing that
> >
> > * cpufreq interface should be used for changing cpu frequency
> the patch set i sent out has cpufreq used for changing cpu frequency,
> hasn't it?

I was talking about kernel<->user interface.

You did echo low > something to change CPU frequency, IIRC.

> can we eventually start talking more close to the code rather than
> speculating without it?

Lets get kernel<->user interface right, first. You'll need to create
Documentation/ entries for your interfaces, eventually, so lets do
that, first, and then talk about code. Oh and it would be nice to cc
lkml on that document, too. New kernel<->user interface is not
decision taken lightly.
									Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Eugeny S. Mints]

Pavel Machek wrote:
> Hi!
> 
> On Mon 2006-09-11 11:57:28, Eugeny S. Mints wrote:
>> [snip]
>>>> Are you arguing that the cpufreq interface be morphed to support power
>>>> op applications?
>>> No. I'm arguing that
>>>
>>> * cpufreq interface should be used for changing cpu frequency
>> the patch set i sent out has cpufreq used for changing cpu frequency,
>> hasn't it?
> 
> I was talking about kernel<->user interface.
me too. PowerOP is inkernel interface but which _allows_ to build various
different kernel<->user interfaces on top of it. This PowerOP _advantage_ allows 
community to experiment with various kernel<->user interfaces on top and 
eventually end up with the best solution. The solution can be either one 
universal, agreed by community kernel<-> user interface on top or I can imaging 
the approach when kernel<-> user interfaces on top are configurable feature and 
system designer choses kernel<->user interface which fits best the systems 
he/she builds.
> 
> You did echo low > something to change CPU frequency, IIRC.
My patch set presents two different interfaces built on top of PowerOP - cpufreq 
and sysfs interfaces. So _no_, PowerOP is not all about 'echo low > something'. 
Such kernel<-> user interface is  an _option_. PowerOP supports full _legacy_ 
cpufreq interface as another option - please check out PowerOP/cpufreq 
integration patch set. The goal is either to end up with one kernel<->user 
interface which addresses both pc world and embedded world requirements to 
user<->kernel interface _or_ - as an alternative I'd prefer - have these 
kernel<->user interfaces configurable: if you build laptop  system - chose 
cpufreq interface on top of PowerOP; if you build embedded - chose sysfs 
interface. But with the approach when everything is built on top PowerOP[PM 
Core, Clock framework] you just eliminate all unnecessary duplication if PM 
functionality in PM  stack.

Just in case you are confused by the fact I didn;t send out PowerOP/cpufreq 
integration patch along with the last PowerOP Core take: PowereOP Core patch I 
sent out in the last take is a standalone functional piece. PowerOP/cpufreq 
integration patch is just a further extension and applies to the most recent 
POwerOP Core without any changes so there was no reason to resend 
PowerOP/cpufreq integration.
> 
>> can we eventually start talking more close to the code rather than
>> speculating without it?
> 
> Lets get kernel<->user interface right, first. You'll need to create
> Documentation/ entries for your interfaces, eventually, so lets do
> that, first, and then talk about code.
Documentation/ piece is fine, I will add it. But I feel I put quite detailed 
comments along with the patches at least to explain interfaces.
> Oh and it would be nice to cc
> lkml on that document, too. New kernel<->user interface is not
> decision taken lightly.
PowerOP Core and PowerOP/cpufreq integration patch sets present two clear and 
configurable kernel<->user interfaces. I personally feel that interfaces 
configuration feature allows graceful interface discussion and possibility to 
get a decision smoothly instead of a flame on a list. If you argue against 
configuration feature please put comments on exactly configuration feature. 
Otherwise please explicitly list the requirements for kernel<->user interface 
you have which are not addressed by these two interfaces assuming you can chose 
either interface having PowerOP underneath.

Thanks,
	Eugeny
> 									Pavel

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Matthew Locke]

I know its confusing having oppoint (from Dave Singleton) and powerop 
being discussed at the same time.  However, I believe we (PowerOP) have 
already address most of the concerns/requirements from the community 
and the embedded folks.  Here is a summary of PowerOP that will 
(hopefully) clear up our approach:

- PowerOP is only one layer (towards the bottom) in a power management 
solution.
- PowerOP does *not* replace cpufreq
- PowerOP can replace the cpufreq_driver layer of cpufreq but cpufreq 
integration not required.
- in kernel cpufreq governors are not directly affect by integrating 
cpufreq and powerop. (Can be extended and/or ported to more 
architectures and operating points)
- Again, cpufreq userspace and kernel interfaces can continue to be 
used as they are today.
- PowerOP defines the parameters you want to change on a per 
architecture/board basis.
- The PowerOP interface was discussed in detail on this list and we 
haven't heard any negative comments.
- We are not advocating the integration with sleep states.  We want to 
get the PowerOP interface accepted and then we can build on it.
- PowerOP is *required* by the embedded folks.

We have a few more comments from Greg to take care of and  we can add a 
Documentation/ file. Then I think its time to get the PowerOP patches 
in the queue for acceptance.    Any comments about this?

btw,  PowerOP<->Cpufreq integration discussion can wait until Dominik 
and Dave Jones have time for more discussion.

On Sep 11, 2006, at 1:20 AM, Pavel Machek wrote:

> Hi!
>
> On Mon 2006-09-11 11:57:28, Eugeny S. Mints wrote:
>> [snip]
>>>> Are you arguing that the cpufreq interface be morphed to support 
>>>> power
>>>> op applications?
>>>
>>> No. I'm arguing that
>>>
>>> * cpufreq interface should be used for changing cpu frequency
>> the patch set i sent out has cpufreq used for changing cpu frequency,
>> hasn't it?
>
> I was talking about kernel<->user interface.
>
> You did echo low > something to change CPU frequency, IIRC.
>
>> can we eventually start talking more close to the code rather than
>> speculating without it?
>
> Lets get kernel<->user interface right, first. You'll need to create
> Documentation/ entries for your interfaces, eventually, so lets do
> that, first, and then talk about code. Oh and it would be nice to cc
> lkml on that document, too. New kernel<->user interface is not
> decision taken lightly.
> 									Pavel
> -- 
> (english) http://www.livejournal.com/~pavelmachek
> (cesky, pictures) 
> http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
>

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Pavel Machek]

Hi!

> >>>>Are you arguing that the cpufreq interface be morphed to support power
> >>>>op applications?
> >>>No. I'm arguing that
> >>>
> >>>* cpufreq interface should be used for changing cpu frequency
> >>the patch set i sent out has cpufreq used for changing cpu frequency,
> >>hasn't it?
> >
> >I was talking about kernel<->user interface.
> me too. PowerOP is inkernel interface but which _allows_ to build various
> different kernel<->user interfaces on top of it. This PowerOP _advantage_ 
> allows community to experiment with various kernel<->user interfaces
>on top 

Kernel interface is not something to be experimented with.

> and eventually end up with the best solution. The solution can be either 
> one universal, agreed by community kernel<-> user interface on top or I can 
> imaging the approach when kernel<-> user interfaces on top are configurable 
> feature and system designer choses kernel<->user interface which fits best 
> the systems he/she builds.

...and configurable kernel interfaces are very bad idea.

> >You did echo low > something to change CPU frequency, IIRC.
> My patch set presents two different interfaces built on top of PowerOP - 
> cpufreq and sysfs interfaces. So _no_, PowerOP is not all about

Okay, drop sysfs interface, and we may have something that can be
reviewed.

Actually that's good idea. Submit powerop without doing _any_ kernel
interface changes, so we can see that it makes sense...

> embedded - chose sysfs interface. But with the approach when everything is 
> built on top PowerOP[PM Core, Clock framework] you just eliminate all 
> unnecessary duplication if PM functionality in PM  stack.

...bonus points if your submission actually deletes more code than it
adds.

> >Oh and it would be nice to cc
> >lkml on that document, too. New kernel<->user interface is not
> >decision taken lightly.
> PowerOP Core and PowerOP/cpufreq integration patch sets present two clear 
> and configurable kernel<->user interfaces. I personally feel that 
> interfaces configuration feature allows graceful interface discussion and 
> possibility to get a decision smoothly instead of a flame on a
>list. 

Your code should be good enough to survive some flaming. I do not
think it is, so yes, I think submitting it to lkml is good
idea. You'll have to do that at some point, anyway.

(And note lkml only flames you when you are doing something wrong.)

								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Matthew Locke]

On Sep 11, 2006, at 12:36 PM, Pavel Machek wrote:

>>> You did echo low > something to change CPU frequency, IIRC.
>> My patch set presents two different interfaces built on top of 
>> PowerOP -
>> cpufreq and sysfs interfaces. So _no_, PowerOP is not all about
>
> Okay, drop sysfs interface, and we may have something that can be
> reviewed.
>

Sysfs is a separate patch that can rejected.  Nothing is stopping 
people from reviewing.


> Actually that's good idea. Submit powerop without doing _any_ kernel
> interface changes, so we can see that it makes sense...


Just to be clear this is the approach we did and are doing.
> Your code should be good enough to survive some flaming. I do not
> think it is, so yes, I think submitting it to lkml is good
> idea. You'll have to do that at some point, anyway.
>
> (And note lkml only flames you when you are doing something wrong.)


Isn't this (linux-pm) the place to discuss power management patches and 
interfaces?  I thought we would get ACK's from the power management 
maintainers and then the patches go into -mm.  Who on lkml needs to be 
in this discussion that is not on this list?

btw, if people on this list are not ready to ACK PowerOP, I would like 
to hear why before we go elsewhere.   It looks like all major issues 
have been addressed by our approach and implementation.

>
> 								Pavel
> -- 
> (english) http://www.livejournal.com/~pavelmachek
> (cesky, pictures) 
> http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
>

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Pavel Machek]

Hi!

> I know its confusing having oppoint (from Dave Singleton) and powerop 
> being discussed at the same time.  However, I believe we (PowerOP)
> have 

Yes, it is.

> - PowerOP is only one layer (towards the bottom) in a power management 
> solution.
> - PowerOP does *not* replace cpufreq

PowerOP provides userland interface for changing processor
frequency. That's bad -- duplicate interface.

> - The PowerOP interface was discussed in detail on this list and we 
> haven't heard any negative comments.

Eh? Was I on different list?

> - We are not advocating the integration with sleep states.  We want to 
> get the PowerOP interface accepted and then we can build on it.

Good.

> We have a few more comments from Greg to take care of and  we can add a 
> Documentation/ file. Then I think its time to get the PowerOP patches 
> in the queue for acceptance.    Any comments about this?

Well, you'll only get good interface review when you have
Documentation/ , and it needs to go to lkml before it goes to any
queues.
								Pavel

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Pavel Machek]

On Mon 2006-09-11 12:53:27, Matthew Locke wrote:
> On Sep 11, 2006, at 12:36 PM, Pavel Machek wrote:
> 
> >>>You did echo low > something to change CPU frequency, IIRC.
> >>My patch set presents two different interfaces built on top of 
> >>PowerOP -
> >>cpufreq and sysfs interfaces. So _no_, PowerOP is not all about
> >
> >Okay, drop sysfs interface, and we may have something that can be
> >reviewed.
> 
> Sysfs is a separate patch that can rejected.  Nothing is stopping 
> people from reviewing.

If you submit patch series with one bad patch, you are very unlikely
to get feedback for the good patches.

> >Actually that's good idea. Submit powerop without doing _any_ kernel
> >interface changes, so we can see that it makes sense...
> 
> Just to be clear this is the approach we did and are doing.

That's not what I remember. Please resubmit, then. And cc lkml this
time.

> btw, if people on this list are not ready to ACK PowerOP, I would like 
> to hear why before we go elsewhere.   It looks like all major issues 
> have been addressed by our approach and implementation.

No, I'm not ready to ACK. Actually I'd describe it as "broken piece of
code noone needs". And IIRC Greg's last question was "what is it good
for?". Dave Jones was not too pleased with cpufreq/powerop
integration. Intel people explained you broke centrino
speedstep. Shall I continue?

								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Pavel Machek]

On Mon 2006-09-11 22:06:36, Pavel Machek wrote:
> On Mon 2006-09-11 12:53:27, Matthew Locke wrote:
> > On Sep 11, 2006, at 12:36 PM, Pavel Machek wrote:

> > btw, if people on this list are not ready to ACK PowerOP, I would like 
> > to hear why before we go elsewhere.   It looks like all major issues 
> > have been addressed by our approach and implementation.

Oh and I am pretty tired of teaching you 'how to submit a patch', so
if I'm quiet, do not take it as an "ACK".
								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Eugeny S. Mints]

Pavel Machek wrote:
> Hi!
> 
>>>>>> Are you arguing that the cpufreq interface be morphed to support power
>>>>>> op applications?
>>>>> No. I'm arguing that
>>>>>
>>>>> * cpufreq interface should be used for changing cpu frequency
>>>> the patch set i sent out has cpufreq used for changing cpu frequency,
>>>> hasn't it?
>>> I was talking about kernel<->user interface.
>> me too. PowerOP is inkernel interface but which _allows_ to build various
>> different kernel<->user interfaces on top of it. This PowerOP _advantage_ 
>> allows community to experiment with various kernel<->user interfaces
>> on top 
> 
> Kernel interface is not something to be experimented with.
it is since current interface (cpufreq in conjunction with /sys/power/state, 
etc) does not address all requirements to the interface. PowerOP approach helps 
to figure out best interface gracefully since there is no common opinion in the 
community yet.
> 
>> and eventually end up with the best solution. The solution can be either 
>> one universal, agreed by community kernel<-> user interface on top or I can 
>> imaging the approach when kernel<-> user interfaces on top are configurable 
>> feature and system designer choses kernel<->user interface which fits best 
>> the systems he/she builds.
> 
> ...and configurable kernel interfaces are very bad idea.
it's not an argument. the ideal goal to end up with one universal interface. but 
until you personally stuck with cpufreq interface this is the only way to 
proceed towards universal interface design. let people to investigate advantages 
and disadvantages of this and that interfaces on a working system since we can't 
convince each other by this flame.
> 
>>> You did echo low > something to change CPU frequency, IIRC.
>> My patch set presents two different interfaces built on top of PowerOP - 
>> cpufreq and sysfs interfaces. So _no_, PowerOP is not all about
> 
> Okay, drop sysfs interface, and we may have something that can be
> reviewed.
previous take of PowerOP did not contain sysfs part but I have not received any 
you comment on this. Sysfs is completely optional feature after all.
 >
> Actually that's good idea. Submit powerop without doing _any_ kernel
> interface changes, so we can see that it makes sense...
It was submitted this way several times.

Eugeny

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Matthew Locke]

On Sep 11, 2006, at 1:06 PM, Pavel Machek wrote:

> On Mon 2006-09-11 12:53:27, Matthew Locke wrote:
>> On Sep 11, 2006, at 12:36 PM, Pavel Machek wrote:
>>
>>>>> You did echo low > something to change CPU frequency, IIRC.
>>>> My patch set presents two different interfaces built on top of
>>>> PowerOP -
>>>> cpufreq and sysfs interfaces. So _no_, PowerOP is not all about
>>>
>>> Okay, drop sysfs interface, and we may have something that can be
>>> reviewed.
>>
>> Sysfs is a separate patch that can rejected.  Nothing is stopping
>> people from reviewing.
>
> If you submit patch series with one bad patch, you are very unlikely
> to get feedback for the good patches.
>
>>> Actually that's good idea. Submit powerop without doing _any_ kernel
>>> interface changes, so we can see that it makes sense...
>>
>> Just to be clear this is the approach we did and are doing.
>
> That's not what I remember. Please resubmit, then. And cc lkml this
> time.
>
>> btw, if people on this list are not ready to ACK PowerOP, I would like
>> to hear why before we go elsewhere.   It looks like all major issues
>> have been addressed by our approach and implementation.
>
> No, I'm not ready to ACK. Actually I'd describe it as "broken piece of
> code noone needs".

But people on this list from TI, Nokia, and Motorola have explained why 
its needed.  Also, we explained why in the f2f linux-pm summit.  Can 
you give some concrete reasons why its not needed that have not been 
addressed already?

> And IIRC Greg's last question was "what is it good
> for?".

That was a long time ago and again many people from the embedded 
community have provided lots of answers.

> Dave Jones was not too pleased with cpufreq/powerop
> integration.

Really?!  I don't think he has reviewed our latest integration patches. 
  Our first submission was a result of discussion with Dominik at the 
linux-pm summit.  The latest submission is a result of Dave Jones 
comments.  I think we have addressed all expressed concerns.  I can't 
force anybody to review this stuff and I'm sure Dave is still catching 
up from his vacation.

>  Intel people explained you broke centrino
> speedstep.

I didn't see that.  Was it off-list?  We did not break centrino.  In 
fact we use both the acpi and hardcoded tables just as  cpufreq does.  
If its broken, then it was already broken.

>  Shall I continue?

Please.  Again,  I still say we have addressed all expressed 
concerns/questions/issues.  If you don't feel we have, please give some 
concrete statements that you are concerned about or don't understand.  
As you can see, many people are happy to help explain.

PowerOP is necessary to build the power management software required 
for embedded mobile devices, so we need to reach an understanding.  If 
the power management guys on this list don't understand PowerOP, then 
moving this discussion to lkml isn't going to help.  I much prefer to 
work together to figure out something than throw it over the wall.

>
> 								Pavel
> -- 
> (english) http://www.livejournal.com/~pavelmachek
> (cesky, pictures) 
> http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
>

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Matthew Locke]

On Sep 11, 2006, at 1:09 PM, Pavel Machek wrote:

> On Mon 2006-09-11 22:06:36, Pavel Machek wrote:
>> On Mon 2006-09-11 12:53:27, Matthew Locke wrote:
>>> On Sep 11, 2006, at 12:36 PM, Pavel Machek wrote:
>
>>> btw, if people on this list are not ready to ACK PowerOP, I would 
>>> like
>>> to hear why before we go elsewhere.   It looks like all major issues
>>> have been addressed by our approach and implementation.
>
> Oh and I am pretty tired of teaching you 'how to submit a patch', so
> if I'm quiet, do not take it as an "ACK".

Tired of teaching me?  We are following the same process documented and 
that everyone else is doing.  I just don't understand your reasons for 
not ACKing and requesting we move this discussion to lkml before people 
on this list are ready to ACK.  That has nothing to do with the process 
for submitting a patch.  No teaching involved or necessary.

What does your going quiet mean?  You have had some good feedback so I 
much prefer we reach some sort of understanding.  If your final 
statement is that PowerOP is not needed and you are never going to like 
it or ACK It, let us know.  We can agree to disagree.

> 								Pavel
> -- 
> (english) http://www.livejournal.com/~pavelmachek
> (cesky, pictures) 
> http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
>

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Pavel Machek]

On Tue 2006-09-12 00:24:25, Eugeny S. Mints wrote:
> Pavel Machek wrote:

> >>>I was talking about kernel<->user interface.
> >>me too. PowerOP is inkernel interface but which _allows_ to build various
> >>different kernel<->user interfaces on top of it. This PowerOP _advantage_ 
> >>allows community to experiment with various kernel<->user interfaces
> >>on top 
> >
> >Kernel interface is not something to be experimented with.
> it is since current interface (cpufreq in conjunction with 
> /sys/power/state, etc) does not address all requirements to the
>interface.

Removing kernel interface takes 2+ years. So no, kernel interface is
not something to be experimented with, at least not on mainline.

> >Actually that's good idea. Submit powerop without doing _any_ kernel
> >interface changes, so we can see that it makes sense...
> It was submitted this way several times.

So try again, and cc lkml this time.
								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Eugeny S. Mints]

Pavel Machek wrote:
> Hi!
> 
>> I know its confusing having oppoint (from Dave Singleton) and powerop 
>> being discussed at the same time.  However, I believe we (PowerOP)
>> have 
> 
> Yes, it is.
> 
>> - PowerOP is only one layer (towards the bottom) in a power management 
>> solution.
>> - PowerOP does *not* replace cpufreq
> 
> PowerOP provides userland interface for changing processor
> frequency. That's bad -- duplicate interface.
Basically the biggest problem with cpufreq interface is that cpufreq has "chose
predefined closest to a given frequency" functionality implemented in the
kernel while there is _no_ any reason to have this functionality implemented in
the kernel if we have sysfs interface exported by PowerOP in place - you just
_have_ to keep all possible functionality out of the kernel. CPufreq interface
is just subset of sysfs interface provided by PowerOP and _must_ be implemented
in userspace on top of sysfs interface - this is the proper way to scape
duplication. Such issue with cpufreq<->kernel userspace interface is consequence
of the fact that cpufreq implements incorrect design of PM stack layers and
interfaces. PowerOP solves this issues as well.
> 
>> - The PowerOP interface was discussed in detail on this list and we 
>> haven't heard any negative comments.
> 
> Eh? Was I on different list?vb dfgdfv
> 
>> - We are not advocating the integration with sleep states.  We want to 
>> get the PowerOP interface accepted and then we can build on it.
> 
> Good.
> 
>> We have a few more comments from Greg to take care of and  we can add a 
>> Documentation/ file. Then I think its time to get the PowerOP patches 
>> in the queue for acceptance.    Any comments about this?
> 
> Well, you'll only get good interface review when you have
> Documentation/ , and it needs to go to lkml before it goes to any
> queues.
PM stack is too complex and heavy part to go in such pieces thru lkml. i expect 
all linux  pm experts to be on this list

Eugeny
> 								Pavel
> 

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Pavel Machek]

> >>- PowerOP is only one layer (towards the bottom) in a power management 
> >>solution.
> >>- PowerOP does *not* replace cpufreq
> >
> >PowerOP provides userland interface for changing processor
> >frequency. That's bad -- duplicate interface.
> Basically the biggest problem with cpufreq interface is that cpufreq has 
> "chose
> predefined closest to a given frequency" functionality implemented in the
> kernel while there is _no_ any reason to have this functionality 
> implemented in
> the kernel if we have sysfs interface exported by PowerOP in place - you 
> just

No, there is reason to keep that in kernel -- so that cpufreq
userspace interface can be kept, and so that resulting kernel<->user
interface is not ugly.

> of the fact that cpufreq implements incorrect design of PM stack layers and
> interfaces. PowerOP solves this issues as well.

Actually I believe that cpufreq implements correct design and PowerOP
got it wrong.

> >Well, you'll only get good interface review when you have
> >Documentation/ , and it needs to go to lkml before it goes to any
> >queues.
> PM stack is too complex and heavy part to go in such pieces thru lkml. i 
> expect all linux  pm experts to be on this list

"We are too lazy to make the code clean enough / well enough explained
to survive lkml review".

Your interface impacts everyone, so everyone should have chance to
comment on it.
								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Pavel Machek]

Hi!

> > Shall I continue?
> 
> Please.  Again,  I still say we have addressed all expressed 
> concerns/questions/issues.  If you don't feel we have, please give some 
> concrete statements that you are concerned about or don't understand.  
> As you can see, many people are happy to help explain.

YOU GOT THE KERNEL<->USER INTERFACE WRONG.
								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Pavel Machek]

On Mon 2006-09-11 13:33:00, Matthew Locke wrote:
> On Sep 11, 2006, at 1:09 PM, Pavel Machek wrote:
> >On Mon 2006-09-11 22:06:36, Pavel Machek wrote:
> >>On Mon 2006-09-11 12:53:27, Matthew Locke wrote:
> >>>On Sep 11, 2006, at 12:36 PM, Pavel Machek wrote:
> >
> >>>btw, if people on this list are not ready to ACK PowerOP, I would 
> >>>like
> >>>to hear why before we go elsewhere.   It looks like all major issues
> >>>have been addressed by our approach and implementation.
> >
> >Oh and I am pretty tired of teaching you 'how to submit a patch', so
> >if I'm quiet, do not take it as an "ACK".
...
> What does your going quiet mean?  You have had some good feedback so I 
> much prefer we reach some sort of understanding.  If your final 
> statement is that PowerOP is not needed and you are never going to like 
> it or ACK It, let us know.  We can agree to disagree.

You got the interfaces wrong. While I believe that something like
powerop can indeed be useful for system-on-chip platforms, I do not
think it should be exposed outside of kernel.
								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Preece Scott-PREECE]

> From: Pavel Machek [mailto:pavel@ucw.cz] 
> 
> > >>- PowerOP is only one layer (towards the bottom) in a power 
> > >>management solution.
> > >>- PowerOP does *not* replace cpufreq
> > >
> > >PowerOP provides userland interface for changing processor 
> frequency. 
> > >That's bad -- duplicate interface.
> > Basically the biggest problem with cpufreq interface is 
> that cpufreq 
> > has "chose predefined closest to a given frequency" functionality 
> > implemented in the kernel while there is _no_ any reason to 
> have this 
> > functionality implemented in the kernel if we have sysfs interface 
> > exported by PowerOP in place - you just
> 
> No, there is reason to keep that in kernel -- so that cpufreq 
> userspace interface can be kept, and so that resulting 
> kernel<->user interface is not ugly.
---

Just as a data point, "keeping the cpufreq interface" is
irrelevant to a number of us, because we configure it out
of the system.  I'm not really arguing that we should get
rid of an existing kernel interface, but I don't see any
reason why we shouldn't be able to have a separately
configurable interface if cpufreq doesn't meet our needs.

Note that Matthew is not arguing even that and expresses
apparent contentment with cpufreq's interface.

Regards,
scott

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Pavel Machek]

On Mon 2006-09-11 17:36:33, Preece Scott-PREECE wrote:
> 
> > From: Pavel Machek [mailto:pavel@ucw.cz] 
> > 
> > > >>- PowerOP is only one layer (towards the bottom) in a power 
> > > >>management solution.
> > > >>- PowerOP does *not* replace cpufreq
> > > >
> > > >PowerOP provides userland interface for changing processor 
> > frequency. 
> > > >That's bad -- duplicate interface.
> > > Basically the biggest problem with cpufreq interface is 
> > that cpufreq 
> > > has "chose predefined closest to a given frequency" functionality 
> > > implemented in the kernel while there is _no_ any reason to 
> > have this 
> > > functionality implemented in the kernel if we have sysfs interface 
> > > exported by PowerOP in place - you just
> > 
> > No, there is reason to keep that in kernel -- so that cpufreq 
> > userspace interface can be kept, and so that resulting 
> > kernel<->user interface is not ugly.
> ---
> 
> Just as a data point, "keeping the cpufreq interface" is
> irrelevant to a number of us, because we configure it out
> of the system.  I'm not really arguing that we should get
> rid of an existing kernel interface, but I don't see any
> reason why we shouldn't be able to have a separately
> configurable interface if cpufreq doesn't meet our needs.

Configurable interfaces are evil, and I do not think you can push such
patch. You have developed your own little interface that suits your
needs -- and that's fine -- but now you are trying to push it into
mainline... and that is not, because those interfaces were not really
designed to work together.
								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Matthew Locke]

On Sep 11, 2006, at 2:06 PM, Pavel Machek wrote:

> On Mon 2006-09-11 13:33:00, Matthew Locke wrote:
>> On Sep 11, 2006, at 1:09 PM, Pavel Machek wrote:
>>> On Mon 2006-09-11 22:06:36, Pavel Machek wrote:
>>>> On Mon 2006-09-11 12:53:27, Matthew Locke wrote:
>>>>> On Sep 11, 2006, at 12:36 PM, Pavel Machek wrote:
>>>
>>>>> btw, if people on this list are not ready to ACK PowerOP, I would
>>>>> like
>>>>> to hear why before we go elsewhere.   It looks like all major 
>>>>> issues
>>>>> have been addressed by our approach and implementation.
>>>
>>> Oh and I am pretty tired of teaching you 'how to submit a patch', so
>>> if I'm quiet, do not take it as an "ACK".
> ...
>> What does your going quiet mean?  You have had some good feedback so I
>> much prefer we reach some sort of understanding.  If your final
>> statement is that PowerOP is not needed and you are never going to 
>> like
>> it or ACK It, let us know.  We can agree to disagree.
>
> You got the interfaces wrong. While I believe that something like
> powerop can indeed be useful for system-on-chip platforms, I do not
> think it should be exposed outside of kernel.


Ok.  I don't think its wrong because its designed from understanding 
the requirements of pm software for embedded mobile devices.   I think 
the embedded folk all agree that the type of interface submitted is 
required.  I don't understand why you think its wrong.  Just to be 
clear, your previous email made it very clear you don't like the 
userspace interface but this email says interfaces generically.  I am 
assuming your only objection at this point is the userspace interface.  
  We are more than willing to work this out.  The current sysfs 
interface is surrounded by ifdefs and is optional.  If there is no 
exposure to userspace, then testing/debuging will be more difficult.

Greg, Pavel, Dominik, Dave J and Dave B,

I would like to get a plan in place for acceptance with the power 
management guys before we move this to lkml.  I propose that we submit 
the current set of PowerOP patches plus final few changes (from Greg's 
comments and a Documentation/ file).  The patches do not affect anyone 
else.  The sysfs interface is optional.  If necessary Eugeny and I will 
maintain userspace interface patches outside the mainline for now.  
Will any of the power management maintainers ACK this plan and then ACK 
the patches?  If no one here is willing to ACK, then I don't see what 
will change by submitting to lkml.


> 								Pavel
> -- 
> (english) http://www.livejournal.com/~pavelmachek
> (cesky, pictures) 
> http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
>

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Mark Gross]

On Mon, Sep 11, 2006 at 10:20:25AM +0200, Pavel Machek wrote:
> Hi!
> 
> On Mon 2006-09-11 11:57:28, Eugeny S. Mints wrote:
> > [snip]
> > >> Are you arguing that the cpufreq interface be morphed to support power
> > >> op applications?
> > >
> > > No. I'm arguing that
> > >
> > > * cpufreq interface should be used for changing cpu frequency
> > the patch set i sent out has cpufreq used for changing cpu frequency,
> > hasn't it?
> 
> I was talking about kernel<->user interface.
> 
> You did echo low > something to change CPU frequency, IIRC.
> 
> > can we eventually start talking more close to the code rather than
> > speculating without it?
> 
> Lets get kernel<->user interface right, first. You'll need to create
> Documentation/ entries for your interfaces, eventually, so lets do
> that, first, and then talk about code. Oh and it would be nice to cc
> lkml on that document, too. New kernel<->user interface is not
> decision taken lightly.

Is this just trying delay power op getting into the kernel?  We are
building up / evolving a PM stack from bottom up and you want to the
high level interface to be well defined and agreed upon first?  

I think the kernel user interface is important too but you are asking
for a complete solution stack when we are following an evolutionary
development process.  

--mgross

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Mark Gross]

On Mon, Sep 11, 2006 at 10:06:36PM +0200, Pavel Machek wrote:
> On Mon 2006-09-11 12:53:27, Matthew Locke wrote:
> > On Sep 11, 2006, at 12:36 PM, Pavel Machek wrote:
> > 
> > >>>You did echo low > something to change CPU frequency, IIRC.
> > >>My patch set presents two different interfaces built on top of 
> > >>PowerOP -
> > >>cpufreq and sysfs interfaces. So _no_, PowerOP is not all about
> > >
> > >Okay, drop sysfs interface, and we may have something that can be
> > >reviewed.
> > 
> > Sysfs is a separate patch that can rejected.  Nothing is stopping 
> > people from reviewing.
> 
> If you submit patch series with one bad patch, you are very unlikely
> to get feedback for the good patches.
> 
> > >Actually that's good idea. Submit powerop without doing _any_ kernel
> > >interface changes, so we can see that it makes sense...
> > 
> > Just to be clear this is the approach we did and are doing.
> 
> That's not what I remember. Please resubmit, then. And cc lkml this
> time.
> 
> > btw, if people on this list are not ready to ACK PowerOP, I would like 
> > to hear why before we go elsewhere.   It looks like all major issues 
> > have been addressed by our approach and implementation.
> 
> No, I'm not ready to ACK. Actually I'd describe it as "broken piece of
> code noone needs". And IIRC Greg's last question was "what is it good
> for?". Dave Jones was not too pleased with cpufreq/powerop
> integration. Intel people explained you broke centrino
> speedstep. Shall I continue?
> 

Those where directed to the other patch that David Singleton posted.


> 								Pavel
> -- 
> (english) http://www.livejournal.com/~pavelmachek
> (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Eugeny S. Mints]

Pavel Machek wrote:
>>>> - PowerOP is only one layer (towards the bottom) in a power management 
>>>> solution.
>>>> - PowerOP does *not* replace cpufreq
>>> PowerOP provides userland interface for changing processor
>>> frequency. That's bad -- duplicate interface.
>> Basically the biggest problem with cpufreq interface is that cpufreq has 
>> "chose
>> predefined closest to a given frequency" functionality implemented in the
>> kernel while there is _no_ any reason to have this functionality 
>> implemented in
>> the kernel if we have sysfs interface exported by PowerOP in place - you 
>> just
> 
> No, there is reason to keep that in kernel -- so that cpufreq
> userspace interface can be kept, and so that resulting kernel<->user
> interface is not ugly.
Cpuferq defines cpufreq_frequency_table structure in arch independent header 
while it's arch dependent data structure. A lot of code is built around this 
invalid basic brick and therefore is invalid: cpufreq tables, interface with cpu 
freq drivers, etc. Notion of transition latency as it defined by cpufreq is 
wrong because it's not a function of cpu type but function of current and next 
operating point. no runtime control on operating points set. it's always the 
same set of operating points for all system cpus in smp case and no way to 
define different sets or track any dependencies in case say multi core cpus. 
insufficient kernel<->user space interface to handle embedded requirements and 
no way to extend it within current design. Shall I continue?  Why should then 
anyone want to keep cpufreq userspace interface just due to keep it?
> 
>> of the fact that cpufreq implements incorrect design of PM stack layers and
>> interfaces. PowerOP solves this issues as well.
> 
> Actually I believe that cpufreq implements correct design and PowerOP
> got it wrong.
PowerOP/cufreq integration patch set contains very details explanation of the 
cpufreq design issues and POwerOP solutions. Comment there is you feel it's wrong.

Eugeny
> 
>>> Well, you'll only get good interface review when you have
>>> Documentation/ , and it needs to go to lkml before it goes to any
>>> queues.
>> PM stack is too complex and heavy part to go in such pieces thru lkml. i 
>> expect all linux  pm experts to be on this list
> 
> "We are too lazy to make the code clean enough / well enough explained
> to survive lkml review".
> 
> Your interface impacts everyone, so everyone should have chance to
> comment on it.
> 								Pavel

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Matthew Locke]

On Sep 11, 2006, at 3:00 PM, Mark Gross wrote:

> On Mon, Sep 11, 2006 at 10:06:36PM +0200, Pavel Machek wrote:
>> No, I'm not ready to ACK. Actually I'd describe it as "broken piece of
>> code noone needs". And IIRC Greg's last question was "what is it good
>> for?". Dave Jones was not too pleased with cpufreq/powerop
>> integration. Intel people explained you broke centrino
>> speedstep. Shall I continue?
>>
>
> Those where directed to the other patch that David Singleton posted.
>

Right.

  Pavel and others,  I know its confusing having the two.  Let's focus 
on just PowerOP.  The PowerOP patches are just powerop and do not 
affect other subsystems or existing PM code.  The other stuff (cpufreq 
integration, suspend/resume integration) can come later.   Nothing in 
PowerOP prevents us from adding more later.

>
>> 								Pavel
>> -- 
>> (english) http://www.livejournal.com/~pavelmachek
>> (cesky, pictures) 
>> http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
>

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Eugeny S. Mints]

Pavel Machek wrote:
> On Mon 2006-09-11 17:36:33, Preece Scott-PREECE wrote:
>>> From: Pavel Machek [mailto:pavel@ucw.cz] 
>>>
>>>>>> - PowerOP is only one layer (towards the bottom) in a power 
>>>>>> management solution.
>>>>>> - PowerOP does *not* replace cpufreq
>>>>> PowerOP provides userland interface for changing processor 
>>> frequency. 
>>>>> That's bad -- duplicate interface.
>>>> Basically the biggest problem with cpufreq interface is 
>>> that cpufreq 
>>>> has "chose predefined closest to a given frequency" functionality 
>>>> implemented in the kernel while there is _no_ any reason to 
>>> have this 
>>>> functionality implemented in the kernel if we have sysfs interface 
>>>> exported by PowerOP in place - you just
>>> No, there is reason to keep that in kernel -- so that cpufreq 
>>> userspace interface can be kept, and so that resulting 
>>> kernel<->user interface is not ugly.
>> ---
>>
>> Just as a data point, "keeping the cpufreq interface" is
>> irrelevant to a number of us, because we configure it out
>> of the system.  I'm not really arguing that we should get
>> rid of an existing kernel interface, but I don't see any
>> reason why we shouldn't be able to have a separately
>> configurable interface if cpufreq doesn't meet our needs.
> 
> Configurable interfaces are evil,
Are you saying that not having sysfs attribute nodes for entities which don't 
exist in a certain configuration is evil?

In x86 configuration you'd like to have just one attribute - frequency? It's 
just subset of common case when all power parameters available on a platform are 
exported. In x86 configuration you'd like to echo arbitrary frequency value into 
'sys/something' and have underneath logic to chose "closest" predefine 
frequency? No any reason to handle this in the kernel once frequency attribute 
is exported.
> and I do not think you can push such
> patch. You have developed your own little interface that suits your
> needs -- and that's fine -- but now you are trying to push it into
> mainline... and that is not, because those interfaces were not really
> designed to work together.
once cpufreq userland interface functionality which does not belong to the 
kernel is moved out of the kernel cpufreq interface becomes a subset of PowerOP 
  sysfs interface. In other words this means that improvements of PM stack 
layers/interfaces design will allow to design/develop an universal userspace 
interface. We'd prefer to move gracefully in this direction though.

	Eugeny
> 								Pavel

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Pavel Machek]

On Mon 2006-09-11 14:53:03, Mark Gross wrote:
> On Mon, Sep 11, 2006 at 10:20:25AM +0200, Pavel Machek wrote:
> > Lets get kernel<->user interface right, first. You'll need to create
> > Documentation/ entries for your interfaces, eventually, so lets do
> > that, first, and then talk about code. Oh and it would be nice to cc
> > lkml on that document, too. New kernel<->user interface is not
> > decision taken lightly.
> 
> Is this just trying delay power op getting into the kernel?  We are
> building up / evolving a PM stack from bottom up and you want to the
> high level interface to be well defined and agreed upon first?

As long as you do not introduce _any_ user<->kernel interfaces within
patch series, going without Documentation is okay. But IIRC that was
not the case.


-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Pavel Machek]

> >>What does your going quiet mean?  You have had some good feedback so I
> >>much prefer we reach some sort of understanding.  If your final
> >>statement is that PowerOP is not needed and you are never going to 
> >>like
> >>it or ACK It, let us know.  We can agree to disagree.
> >
> >You got the interfaces wrong. While I believe that something like
> >powerop can indeed be useful for system-on-chip platforms, I do not
> >think it should be exposed outside of kernel.
> 
> 
> Ok.  I don't think its wrong because its designed from understanding 
> the requirements of pm software for embedded mobile devices.   I
>think 
> the embedded folk all agree that the type of interface submitted is 
> required.  I don't understand why you think its wrong.  Just to be 

So you'll have to do lots of explaining. On lkml.

> clear, your previous email made it very clear you don't like the 
> userspace interface but this email says interfaces generically.  

I meant user<->kernel interface.

> assuming your only objection at this point is the userspace interface.  
>  We are more than willing to work this out.  The current sysfs 
> interface is surrounded by ifdefs and is optional.  If there is no 
> exposure to userspace, then testing/debuging will be more difficult.

Having interface surrounded by #ifdefs is evil. You can test it
separately, then just remove that code before submission. Or maybe
move it to debugfs.

> Greg, Pavel, Dominik, Dave J and Dave B,
> 
> I would like to get a plan in place for acceptance with the power 
> management guys before we move this to lkml.  

Documentation/SubmittingPatches says:
#5) Select your CC (e-mail carbon copy) list.
#
#Unless you have a reason NOT to do so, CC
#linux-kernel@vger.kernel.org.

and sorry, but I insist on using proper procedure here. And no, "we
are afraid of being flamed" is not good enough reason not to.
								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

cpufreq terminally broken [was Re: community PM requirements/issues and PowerOP]

[Pavel Machek]

Hi!

Just for the record... this goes out to the lkml. This discussion was
internal for way too long. (for interested lkml readers, I'm sure
linux-pm mailing list has public archive somewhere).

On Tue 2006-09-12 02:05:26, Eugeny S. Mints wrote:
> Pavel Machek wrote:
> >>>>- PowerOP is only one layer (towards the bottom) in a power management 
> >>>>solution.
> >>>>- PowerOP does *not* replace cpufreq
> >>>PowerOP provides userland interface for changing processor
> >>>frequency. That's bad -- duplicate interface.
> >>Basically the biggest problem with cpufreq interface is that cpufreq has 
> >>"chose
> >>predefined closest to a given frequency" functionality implemented in the
> >>kernel while there is _no_ any reason to have this functionality 
> >>implemented in
> >>the kernel if we have sysfs interface exported by PowerOP in place - you 
> >>just
> >
> >No, there is reason to keep that in kernel -- so that cpufreq
> >userspace interface can be kept, and so that resulting kernel<->user
> >interface is not ugly.
> Cpuferq defines cpufreq_frequency_table structure in arch independent 
> header while it's arch dependent data structure. A lot of code is built 
> around this invalid basic brick and therefore is invalid: cpufreq tables, 
> interface with cpu freq drivers, etc. Notion of transition latency as it 
> defined by cpufreq is wrong because it's not a function of cpu type but 
> function of current and next operating point. no runtime control on 
> operating points set. it's always the same set of operating points for all 
> system cpus in smp case and no way to define different sets or track any 
> dependencies in case say multi core cpus. insufficient kernel<->user space 
> interface to handle embedded requirements and no way to extend it within 
> current design. Shall I continue?  Why should then anyone want to keep 
> cpufreq userspace interface just due to keep it?

Yes, please continue. I do not think we can just rip cpufreq interface
out of kernel, and I do not think it is as broken as you claim it
is. Ripping interface out of kernel takes years.

I'm sure cpufreq_frequency_table could be moved to asm/ header if you
felt strongly about that.

I believe we need to fix cpufreq if it is broken for embedded
cases.
								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

cpufreq terminally broken [was Re: community PM requirements/issues and PowerOP]

[Pavel Machek]

Hi!

Just for the record... this goes out to the lkml. This discussion was
internal for way too long. (for interested lkml readers, I'm sure
linux-pm mailing list has public archive somewhere).

On Tue 2006-09-12 02:05:26, Eugeny S. Mints wrote:
> Pavel Machek wrote:
> >>>>- PowerOP is only one layer (towards the bottom) in a power management 
> >>>>solution.
> >>>>- PowerOP does *not* replace cpufreq
> >>>PowerOP provides userland interface for changing processor
> >>>frequency. That's bad -- duplicate interface.
> >>Basically the biggest problem with cpufreq interface is that cpufreq has 
> >>"chose
> >>predefined closest to a given frequency" functionality implemented in the
> >>kernel while there is _no_ any reason to have this functionality 
> >>implemented in
> >>the kernel if we have sysfs interface exported by PowerOP in place - you 
> >>just
> >
> >No, there is reason to keep that in kernel -- so that cpufreq
> >userspace interface can be kept, and so that resulting kernel<->user
> >interface is not ugly.
> Cpuferq defines cpufreq_frequency_table structure in arch independent 
> header while it's arch dependent data structure. A lot of code is built 
> around this invalid basic brick and therefore is invalid: cpufreq tables, 
> interface with cpu freq drivers, etc. Notion of transition latency as it 
> defined by cpufreq is wrong because it's not a function of cpu type but 
> function of current and next operating point. no runtime control on 
> operating points set. it's always the same set of operating points for all 
> system cpus in smp case and no way to define different sets or track any 
> dependencies in case say multi core cpus. insufficient kernel<->user space 
> interface to handle embedded requirements and no way to extend it within 
> current design. Shall I continue?  Why should then anyone want to keep 
> cpufreq userspace interface just due to keep it?

Yes, please continue. I do not think we can just rip cpufreq interface
out of kernel, and I do not think it is as broken as you claim it
is. Ripping interface out of kernel takes years.

I'm sure cpufreq_frequency_table could be moved to asm/ header if you
felt strongly about that.

I believe we need to fix cpufreq if it is broken for embedded
cases.
								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

cpufreq user<->kernel interface removal [was Re: community PM requirements/issues and PowerOP]

[Pavel Machek]

Hi!

(cc-ed to lkml).

> >>Just as a data point, "keeping the cpufreq interface" is
> >>irrelevant to a number of us, because we configure it out
> >>of the system.  I'm not really arguing that we should get
> >>rid of an existing kernel interface, but I don't see any
> >>reason why we shouldn't be able to have a separately
> >>configurable interface if cpufreq doesn't meet our needs.
> >
> >Configurable interfaces are evil,
> Are you saying that not having sysfs attribute nodes for entities which 
> don't exist in a certain configuration is evil?

I'm saying that

#ifdef CONFIG_FOO
	provide user<->kernel interface
#endif

is evil.

> >patch. You have developed your own little interface that suits your
> >needs -- and that's fine -- but now you are trying to push it into
> >mainline... and that is not, because those interfaces were not really
> >designed to work together.

> once cpufreq userland interface functionality which does not belong to the 
> kernel is moved out of the kernel cpufreq interface becomes a subset of 
> PowerOP sysfs interface. In other words this means that improvements of PM 
>  stack layers/interfaces design will allow to design/develop an universal 
> userspace interface. We'd prefer to move gracefully in this direction 
> though.

<tongue-in-cheek warning>

Yes, once cpufreq userland interface is removed from kernel, merging
powerop is reasonable thing to do. But please get at least
Documentation/feature-removal-schedule.txt patch merged to mainline
before attempting next powerop submission :-P.

<I'm trying to explain that removing cpufreq userland interface is
about as probable as MS Linux, and only a bit less likely than hell
freezing over.>
								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: cpufreq user<->kernel interface removal [was Re: community PM requirements/issues and PowerOP]

[Mark Gross]

On Tue, Sep 12, 2006 at 01:05:29AM +0200, Pavel Machek wrote:
> Hi!
> 
> (cc-ed to lkml).
> 
> > >>Just as a data point, "keeping the cpufreq interface" is
> > >>irrelevant to a number of us, because we configure it out
> > >>of the system.  I'm not really arguing that we should get
> > >>rid of an existing kernel interface, but I don't see any
> > >>reason why we shouldn't be able to have a separately
> > >>configurable interface if cpufreq doesn't meet our needs.
> > >
> > >Configurable interfaces are evil,
> > Are you saying that not having sysfs attribute nodes for entities which 
> > don't exist in a certain configuration is evil?
> 
> I'm saying that
> 
> #ifdef CONFIG_FOO
> 	provide user<->kernel interface
> #endif
> 
> is evil.
>

I disagree.

> > >patch. You have developed your own little interface that suits your
> > >needs -- and that's fine -- but now you are trying to push it into
> > >mainline... and that is not, because those interfaces were not really
> > >designed to work together.
> 
> > once cpufreq userland interface functionality which does not belong to the 
> > kernel is moved out of the kernel cpufreq interface becomes a subset of 
> > PowerOP sysfs interface. In other words this means that improvements of PM 
> >  stack layers/interfaces design will allow to design/develop an universal 
> > userspace interface. We'd prefer to move gracefully in this direction 
> > though.
> 
> <tongue-in-cheek warning>
> 
> Yes, once cpufreq userland interface is removed from kernel, merging
> powerop is reasonable thing to do. But please get at least
> Documentation/feature-removal-schedule.txt patch merged to mainline
> before attempting next powerop submission :-P.
> 
> <I'm trying to explain that removing cpufreq userland interface is
> about as probable as MS Linux, and only a bit less likely than hell
> freezing over.>

The PowerOP patch has nothing to do with the removal of cpufreq.  You
may be confusing this work with the david signleton patch.

--mgross

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Mark Gross]

On Tue, Sep 12, 2006 at 12:43:13AM +0200, Pavel Machek wrote:
> On Mon 2006-09-11 14:53:03, Mark Gross wrote:
> > On Mon, Sep 11, 2006 at 10:20:25AM +0200, Pavel Machek wrote:
> > > Lets get kernel<->user interface right, first. You'll need to create
> > > Documentation/ entries for your interfaces, eventually, so lets do
> > > that, first, and then talk about code. Oh and it would be nice to cc
> > > lkml on that document, too. New kernel<->user interface is not
> > > decision taken lightly.
> > 
> > Is this just trying delay power op getting into the kernel?  We are
> > building up / evolving a PM stack from bottom up and you want to the
> > high level interface to be well defined and agreed upon first?
> 
> As long as you do not introduce _any_ user<->kernel interfaces within
> patch series, going without Documentation is okay. But IIRC that was
> not the case.
> 

I don't think providing Documentation on whatever interface will be a
problem.

--mgross

Re: cpufreq terminally broken [was Re: community PM requirements/issues and PowerOP]

[Mark Gross]

On Tue, Sep 12, 2006 at 12:56:17AM +0200, Pavel Machek wrote:
> Hi!
> 
> Just for the record... this goes out to the lkml. This discussion was
> internal for way too long. (for interested lkml readers, I'm sure
> linux-pm mailing list has public archive somewhere).
>

This was rude.

> On Tue 2006-09-12 02:05:26, Eugeny S. Mints wrote:
> > Pavel Machek wrote:
> > >>>>- PowerOP is only one layer (towards the bottom) in a power management 
> > >>>>solution.
> > >>>>- PowerOP does *not* replace cpufreq
> > >>>PowerOP provides userland interface for changing processor
> > >>>frequency. That's bad -- duplicate interface.
> > >>Basically the biggest problem with cpufreq interface is that cpufreq has 
> > >>"chose
> > >>predefined closest to a given frequency" functionality implemented in the
> > >>kernel while there is _no_ any reason to have this functionality 
> > >>implemented in
> > >>the kernel if we have sysfs interface exported by PowerOP in place - you 
> > >>just
> > >
> > >No, there is reason to keep that in kernel -- so that cpufreq
> > >userspace interface can be kept, and so that resulting kernel<->user
> > >interface is not ugly.
> > Cpuferq defines cpufreq_frequency_table structure in arch independent 
> > header while it's arch dependent data structure. A lot of code is built 
> > around this invalid basic brick and therefore is invalid: cpufreq tables, 
> > interface with cpu freq drivers, etc. Notion of transition latency as it 
> > defined by cpufreq is wrong because it's not a function of cpu type but 
> > function of current and next operating point. no runtime control on 
> > operating points set. it's always the same set of operating points for all 
> > system cpus in smp case and no way to define different sets or track any 
> > dependencies in case say multi core cpus. insufficient kernel<->user space 
> > interface to handle embedded requirements and no way to extend it within 
> > current design. Shall I continue?  Why should then anyone want to keep 
> > cpufreq userspace interface just due to keep it?
> 
> Yes, please continue. I do not think we can just rip cpufreq interface
> out of kernel, and I do not think it is as broken as you claim it
> is. Ripping interface out of kernel takes years.
> 
> I'm sure cpufreq_frequency_table could be moved to asm/ header if you
> felt strongly about that.
> 
> I believe we need to fix cpufreq if it is broken for embedded
> cases.

cpufreq is broken at the cpufreq_driver interface for embedded
applications needing control over more than one control variable at a
time.

That interface only supports setting target frequencies, and expanding it
to set target frequencies and voltages is not possible without something
like PowerOP.  Adding the types of parameters to cpufreq would likely
make cpufreq a mess.  I think we would be better off with something that
coexists with cpufreq, like the powerop patch from Eugeny.

God help you if you try to use cpufreq on a complex non-PC platform with
multiple power and clock domains that need to be tweaked to squeeze out
competitive battery life.

Because of the existing user base of cpufreq removing cpufreq will never
happen.  No one supporting the PowerOP patch has never recommended
such a thing.  However; holding back innovation because of an existing
solution that doesn't support a large class of users seems dumb.

--mgross

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Greg KH]

On Mon, Sep 11, 2006 at 01:25:42PM -0700, Matthew Locke wrote:
> On Sep 11, 2006, at 1:06 PM, Pavel Machek wrote:
> >And IIRC Greg's last question was "what is it good
> >for?".
> 
> That was a long time ago and again many people from the embedded 
> community have provided lots of answers.

I'm still not convinced.  You can't break the current cpufreq interface,
and to claim that it is irrelevant is just ignoring 95% of the Linux
market right now :)

So, you all better work with the cpufreq people, otherwise this code is
going to go nowhere.

I'm with Pavel here, in my opinion, he is correct.

thanks,

greg k-h

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Greg KH]

On Mon, Sep 11, 2006 at 02:50:04PM -0700, Matthew Locke wrote:
> 
> I would like to get a plan in place for acceptance with the power 
> management guys before we move this to lkml.

Sure, let's see something here that we all agree on.  You have yet to
achieve that, so you still have work to do.

> I propose that we submit the current set of PowerOP patches plus final
> few changes (from Greg's comments and a Documentation/ file).

Nothing is keeping you from sending these to the list now.  Please do
so.

> The patches do not affect anyone else.  The sysfs interface is
> optional.

If so, it will be interesting to see why the code is even needed, I
await the patches :)

> If necessary Eugeny and I will maintain userspace interface patches
> outside the mainline for now.

Why?  What good would the in-kernel patches be then if it can't be used
except for some external patches?  That's not acceptable.  And the user
interface has been tied to the other kernel code, so I think you need
them both, but am willing to be convinced otherwise.

> Will any of the power management maintainers ACK this plan and then
> ACK the patches?

Let's see the code please.

> If no one here is willing to ACK, then I don't see what will change by
> submitting to lkml.

Let's get this agreed on first, I feel that you still have some way to
go here.

Sending stuff to lkml is fine too, you should be doing that for such a
core change anyway.  I don't see why you can't do that at the same time,
it's just an extra email on the CC: line...

thanks,

greg k-h

Re: cpufreq user<->kernel interface removal [was Re: community PM requirements/issues and PowerOP]

[Greg KH]

On Mon, Sep 11, 2006 at 04:50:25PM -0700, Mark Gross wrote:
> The PowerOP patch has nothing to do with the removal of cpufreq.  You
> may be confusing this work with the david signleton patch.

I am totally confused about who is working on what, and what provides
what.

Can someone make  quick cheat-sheet that shows the different
developers/companies and projects here?  The fact that it's impossible
to keep this straight in the first place does not bode well...

Or, can each of the different projects send a _short_, 1 paragraph, 4
sentance maximum summary of the different things.  Think of it as your
"elevator pitch".  The different multi-page summaries ware making my
eyes glaze over...

thanks,

greg k-h

Re: cpufreq terminally broken [was Re: community PM requirements/issues and PowerOP]

[Greg KH]

On Mon, Sep 11, 2006 at 05:17:01PM -0700, Mark Gross wrote:
> 
> cpufreq is broken at the cpufreq_driver interface for embedded
> applications needing control over more than one control variable at a
> time.
> 
> That interface only supports setting target frequencies, and expanding it
> to set target frequencies and voltages is not possible without something
> like PowerOP.  Adding the types of parameters to cpufreq would likely
> make cpufreq a mess.  I think we would be better off with something that
> coexists with cpufreq, like the powerop patch from Eugeny.
> 
> God help you if you try to use cpufreq on a complex non-PC platform with
> multiple power and clock domains that need to be tweaked to squeeze out
> competitive battery life.
> 
> Because of the existing user base of cpufreq removing cpufreq will never
> happen.  No one supporting the PowerOP patch has never recommended
> such a thing.  However; holding back innovation because of an existing
> solution that doesn't support a large class of users seems dumb.

But you can't break the existing stuff, and it seems that some of these
proposals are doing just that. :(

thanks,

greg k-h

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Matthew Locke]

On Sep 11, 2006, at 8:31 PM, Greg KH wrote:

> On Mon, Sep 11, 2006 at 02:50:04PM -0700, Matthew Locke wrote:
>>
>> I would like to get a plan in place for acceptance with the power
>> management guys before we move this to lkml.
>
> Sure, let's see something here that we all agree on.  You have yet to
> achieve that, so you still have work to do.
>
>> I propose that we submit the current set of PowerOP patches plus final
>> few changes (from Greg's comments and a Documentation/ file).
>
> Nothing is keeping you from sending these to the list now.  Please do
> so.

The only thing stopping us is time:)  It will happen soon.

>
>> The patches do not affect anyone else.  The sysfs interface is
>> optional.
>
> If so, it will be interesting to see why the code is even needed, I
> await the patches :)

PowerOP patches have been submitted to this list several times for 
review.  You even reviewed a version or two.  The main comments we are 
addressing are small issues such as add a file in Documentation and 
module reference counting.  Not much else will change so you have the 
code.  The cpufreq<->PowerOP integration patches have also been 
submitted but no one has responded to those.

Just read the other emails.  I will stop here.  It's time to reset the 
discussion again.

>
>> If necessary Eugeny and I will maintain userspace interface patches
>> outside the mainline for now.
>
> Why?  What good would the in-kernel patches be then if it can't be used
> except for some external patches?  That's not acceptable.  And the user
> interface has been tied to the other kernel code, so I think you need
> them both, but am willing to be convinced otherwise.

I think so too.  This offer is in response to Pavel's comment that 
PowerOP is ok for in-kernel usage but not userspace.

>
>> Will any of the power management maintainers ACK this plan and then
>> ACK the patches?
>
> Let's see the code please.
>
>> If no one here is willing to ACK, then I don't see what will change by
>> submitting to lkml.
>
> Let's get this agreed on first, I feel that you still have some way to
> go here.
>
> Sending stuff to lkml is fine too, you should be doing that for such a
> core change anyway.  I don't see why you can't do that at the same 
> time,
> it's just an extra email on the CC: line...
>
> thanks,
>
> greg k-h
>

Re: cpufreq terminally broken [was Re: community PM requirements/issues and PowerOP]

[Pavel Machek]

Hi!

> > > >No, there is reason to keep that in kernel -- so that cpufreq
> > > >userspace interface can be kept, and so that resulting kernel<->user
> > > >interface is not ugly.
> > > Cpuferq defines cpufreq_frequency_table structure in arch independent 
> > > header while it's arch dependent data structure. A lot of code is built 
> > > around this invalid basic brick and therefore is invalid: cpufreq tables, 
> > > interface with cpu freq drivers, etc. Notion of transition latency as it 
> > > defined by cpufreq is wrong because it's not a function of cpu type but 
> > > function of current and next operating point. no runtime control on 
> > > operating points set. it's always the same set of operating points for all 
> > > system cpus in smp case and no way to define different sets or track any 
> > > dependencies in case say multi core cpus. insufficient kernel<->user space 
> > > interface to handle embedded requirements and no way to extend it within 
> > > current design. Shall I continue?  Why should then anyone want to keep 
> > > cpufreq userspace interface just due to keep it?
> > 
> > Yes, please continue. I do not think we can just rip cpufreq interface
> > out of kernel, and I do not think it is as broken as you claim it
> > is. Ripping interface out of kernel takes years.
> > 
> > I'm sure cpufreq_frequency_table could be moved to asm/ header if you
> > felt strongly about that.
> > 
> > I believe we need to fix cpufreq if it is broken for embedded
> > cases.
> 
> cpufreq is broken at the cpufreq_driver interface for embedded
> applications needing control over more than one control variable at a
> time.
> 
> That interface only supports setting target frequencies, and expanding it
> to set target frequencies and voltages is not possible without something
> like PowerOP.  Adding the types of parameters to cpufreq would likely
> make cpufreq a mess.

Can we at least try adding that, before deciding cpufreq is unsuitable
and starting new interface? I do not think issues are nearly as big as
you think.. (at user<->kernel interface level, anyway; you'll need big
changes under the hood).
								Pavel

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: cpufreq terminally broken [was Re: community PM requirements/issues and PowerOP]

[Pavel Machek]

Hi!

> > > >No, there is reason to keep that in kernel -- so that cpufreq
> > > >userspace interface can be kept, and so that resulting kernel<->user
> > > >interface is not ugly.
> > > Cpuferq defines cpufreq_frequency_table structure in arch independent 
> > > header while it's arch dependent data structure. A lot of code is built 
> > > around this invalid basic brick and therefore is invalid: cpufreq tables, 
> > > interface with cpu freq drivers, etc. Notion of transition latency as it 
> > > defined by cpufreq is wrong because it's not a function of cpu type but 
> > > function of current and next operating point. no runtime control on 
> > > operating points set. it's always the same set of operating points for all 
> > > system cpus in smp case and no way to define different sets or track any 
> > > dependencies in case say multi core cpus. insufficient kernel<->user space 
> > > interface to handle embedded requirements and no way to extend it within 
> > > current design. Shall I continue?  Why should then anyone want to keep 
> > > cpufreq userspace interface just due to keep it?
> > 
> > Yes, please continue. I do not think we can just rip cpufreq interface
> > out of kernel, and I do not think it is as broken as you claim it
> > is. Ripping interface out of kernel takes years.
> > 
> > I'm sure cpufreq_frequency_table could be moved to asm/ header if you
> > felt strongly about that.
> > 
> > I believe we need to fix cpufreq if it is broken for embedded
> > cases.
> 
> cpufreq is broken at the cpufreq_driver interface for embedded
> applications needing control over more than one control variable at a
> time.
> 
> That interface only supports setting target frequencies, and expanding it
> to set target frequencies and voltages is not possible without something
> like PowerOP.  Adding the types of parameters to cpufreq would likely
> make cpufreq a mess.

Can we at least try adding that, before deciding cpufreq is unsuitable
and starting new interface? I do not think issues are nearly as big as
you think.. (at user<->kernel interface level, anyway; you'll need big
changes under the hood).
								Pavel

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: cpufreq user<->kernel interface removal [was Re: community PM requirements/issues and PowerOP]

[Matthew Locke]

On Sep 11, 2006, at 8:35 PM, Greg KH wrote:

> On Mon, Sep 11, 2006 at 04:50:25PM -0700, Mark Gross wrote:
>> The PowerOP patch has nothing to do with the removal of cpufreq.  You
>> may be confusing this work with the david signleton patch.
>
> I am totally confused about who is working on what, and what provides
> what.
>
> Can someone make  quick cheat-sheet that shows the different
> developers/companies and projects here?  The fact that it's impossible
> to keep this straight in the first place does not bode well...
>
> Or, can each of the different projects send a _short_, 1 paragraph, 4
> sentance maximum summary of the different things.  Think of it as your
> "elevator pitch".  The different multi-page summaries ware making my
> eyes glaze over...
>

Sure, I think that is very necessary right now.  In fact, everyone 
should probably hold off on commenting until this is well understood.

While I think its good to reset the discussion with a high level 
summary, a lot of discussion explaining why PowerOP is required for 
embedded devices has occurred over the last several months that can not 
be summarized in 4 sentences.  People will definitely need to read the 
archives to catch up on the why.

The PowerOP summary will follow soon.

> thanks,
>
> greg k-h
>

Re: [linux-pm] cpufreq terminally broken [was Re: community PM requirements/issues and PowerOP]

[Vitaly Wool]

Pavel,

On 9/12/06, Pavel Machek <pavel@ucw.cz> wrote:
> Can we at least try adding that, before deciding cpufreq is unsuitable
> and starting new interface? I do not think issues are nearly as big as
> you think.. (at user<->kernel interface level, anyway; you'll need big
> changes under the hood).

who talks about user <-> kernel interface level changes at the moment?!

Vitaly

Re: cpufreq terminally broken [was Re: community PM requirements/issues and PowerOP]

[Vitaly Wool]

Pavel,

On 9/12/06, Pavel Machek <pavel@ucw.cz> wrote:
> Can we at least try adding that, before deciding cpufreq is unsuitable
> and starting new interface? I do not think issues are nearly as big as
> you think.. (at user<->kernel interface level, anyway; you'll need big
> changes under the hood).

who talks about user <-> kernel interface level changes at the moment?!

Vitaly

Re: [linux-pm] cpufreq terminally broken [was Re: community PM requirements/issues and PowerOP]

[Pavel Machek]

On Tue 2006-09-12 13:10:24, Vitaly Wool wrote:
> Pavel,
> 
> On 9/12/06, Pavel Machek <pavel@ucw.cz> wrote:
> >Can we at least try adding that, before deciding cpufreq is unsuitable
> >and starting new interface? I do not think issues are nearly as big as
> >you think.. (at user<->kernel interface level, anyway; you'll need big
> >changes under the hood).
> 
> who talks about user <-> kernel interface level changes at the moment?!

Eugeny?
								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: cpufreq terminally broken [was Re: community PM requirements/issues and PowerOP]

[Pavel Machek]

On Tue 2006-09-12 13:10:24, Vitaly Wool wrote:
> Pavel,
> 
> On 9/12/06, Pavel Machek <pavel@ucw.cz> wrote:
> >Can we at least try adding that, before deciding cpufreq is unsuitable
> >and starting new interface? I do not think issues are nearly as big as
> >you think.. (at user<->kernel interface level, anyway; you'll need big
> >changes under the hood).
> 
> who talks about user <-> kernel interface level changes at the moment?!

Eugeny?
								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: [linux-pm] cpufreq terminally broken [was Re: community PM requirements/issues and PowerOP]

[Vitaly Wool]

On 9/12/06, Pavel Machek <pavel@ucw.cz> wrote:
> > who talks about user <-> kernel interface level changes at the moment?!
> Eugeny?

Well, as far as I understood, both parties are ready to talk about
_kernel_ interface at the moment. Let's try to look at it from this
very point of view.
Eugeny, please correct me if my understanding is wrong.

Vitaly

Re: cpufreq user<->kernel interface removal [was Re: community PM requirements/issues and PowerOP]

[Jon Loeliger]

On Mon, 2006-09-11 at 22:35, Greg KH wrote:
> On Mon, Sep 11, 2006 at 04:50:25PM -0700, Mark Gross wrote:
> > The PowerOP patch has nothing to do with the removal of cpufreq.  You
> > may be confusing this work with the david signleton patch.
> 
> I am totally confused about who is working on what, and what provides
> what.

Me too.

> Can someone make  quick cheat-sheet that shows the different
> developers/companies and projects here?  The fact that it's impossible
> to keep this straight in the first place does not bode well...

And while we are summarizing, can we review the strategy
for the large-scale improvements we are contemplating here?
And then maybe even offer a list of ordered steps?

Like, do we all agree/disagree that we should do any/all
of these?

    - Generalize the cpufreq codebase
    - Generalize the cpufreq code with generalized concept
      of Operating Point
    - Unify handling of reduced operating states with
      actual sleep/off states
    - Unify the PowerOP code with the Op Point code
    - Unify the PowerOP, OpPoint, cpufreq and ACPI code
    - Dispense with PM unification entirely and let specific
      implementations emerge for now
    - Rewrite the lowest level of operating point handling
    - Implement a user<->kernel interface for Power Management
    - Allow only kernel control of PM
    - Allow user-level control of PM
    - Allow both/either User and Kernel code to decide on
      PM state transitions
    - Provide distinct code bases at the lowest level for
      handling different components of an operating point
      and recognize cpufreq as one part of that, with other
      parts needing to be written first, before a generalized
      operating point handler can be written at the next layer

I think there has been some focus lost in this discussion,
and I'd like to see a clear delineation of some requirements
and direction just to make sure it is all headed in a common,
right direction.

Thanks,
jdl

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[David Brownell]

Hi Matt,

> From matt@nomadgs.com  Mon Sep 11 14:56:58 2006
>
> Greg, Pavel, Dominik, Dave J and Dave B,
>
> I would like to get a plan in place for acceptance with the power 
> management guys before we move this to lkml.  I propose that we submit 
> the current set of PowerOP patches plus final few changes (from Greg's 
> comments and a Documentation/ file).  The patches do not affect anyone 
> else.  The sysfs interface is optional.  If necessary Eugeny and I will 
> maintain userspace interface patches outside the mainline for now.  
> Will any of the power management maintainers ACK this plan and then ACK 
> the patches?  If no one here is willing to ACK, then I don't see what 
> will change by submitting to lkml.

The Linux-PM list booted me off itself for a while, and I just got
back on and haven't gotten through the backlog yet.  Right now the
distinctions and relationships between any of the "recent patches"
and system-wide mechanisms like

    - lowpower idle tasks;

    - multiple run states ... cpufreq doing an inadequte subset,
      even if you're only interested in CPUs;

    - multiple sleep states ... /sys/power/state listing "standby"
      and/or "mem" (kind of weak for embedded systems) and "disk"
      (which is checkpoint/resume, not really sleep);

are not fully evident to me, so acking anything seems premature.
Plus there's an "ACPI way" to do so much of that, which doesn't
much help most non-x86 systems.

I thought I saw patches generalizing both sleep and run states
(separate patch sets!) ... plus a good comment from Greg that
a short (!) "elevator pitch" seemed to be lacking.

- Dave

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[David Brownell]

> Date: Mon, 11 Sep 2006 21:36:37 +0200
> From: Pavel Machek <pavel@ucw.cz>
>
> Kernel interface is not something to be experimented with.

Disagree.  How else to get it right??
Try, learn, improve.  That's experimentation.
Linux has no "stable API nonsense" ...

The point of "cathedral vs bazaar" was that experimentation
and evolution are more successful processes than "get it right
the first time".


> (And note lkml only flames you when you are doing something wrong.)

Or sometimes, when you post on a day whose name (in English)
ends with a "y"... depends on the topic! ;)

- Dave

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Preece Scott-PREECE]

 
> From: David Brownell [mailto:david-b@pacbell.net] 
> 
> > Date: Mon, 11 Sep 2006 21:36:37 +0200
> > From: Pavel Machek <pavel@ucw.cz>
> >
> > Kernel interface is not something to be experimented with.
> 
> Disagree.  How else to get it right??
> Try, learn, improve.  That's experimentation.
> Linux has no "stable API nonsense" ...
> 
> The point of "cathedral vs. bazaar" was that experimentation 
> and evolution are more successful processes than "get it 
> right the first time".
---

I think Pavel's point was that the userspace interface to 
the kernel (at least the syscall interface) is stable (open to
Extension by addition of syscalls, but closed to modification
or deletion of existing and that any experimentation needs to 
happen before functionality goes into the mainstream. 

That said, I do think we probably need to add a new interface to
cover operating points, because some of believe that policy needs
to be in user space and the whole point of the OP abstraction is 
that operating points are atomic. You can't just add knobs to
control more factors, because all those knobs need to be turned
at the same time. Setting an operating point is inherently an
atomic operation, not n separate operations that can be taken
serially.

scott
 

Re: [linux-pm] cpufreq terminally broken [was Re: community PM requirements/issues and PowerOP]

[David Singleton]

Greg,
   here's a few paragraphs about the power management code I'm working on.
The OpPoint patch set is a fully functionaly power management solution,
from kernel operating state support to userland power manager.

OpPoint constructs operating points for all supported frequency, voltage
and suspend states for PC and SoC solutions running Linux.  OpPoint
does not break or replace cpufreq.  It leverages cpufreq code to provide
the same driver scaling functions when cpu frequency changes affect drivers.

(The ARM pxa27x patch uses the cpufreq scaling routines to scale the LCD
when frequencies are changed and works well when playing mpeg movies on
the LCD during frequency scaling operations).

The Operating Points in OpPoint are simply created at compile time, in
the same manner cpufreq tables are, and registered in
/sys/power/operating_states directory when the cpu is identified at boot time.

The states are ordered by name on their power consumption level from lowest
to highest so the power manager can operate correctly regardless of what
frequencies or voltages are associated with the lowest or highest
operating points.

There is no kernel interface to parse and create all the parameters
needed to create an operating point.  Platform specific information
is supplied to the oppoint structure through an ops vector of three
routines and a void * pointer to supply the platform specific data,
in the same manner drivers have a void * for their private data.

The ops vectors provide operating point specific functions to prepare
to change to a new operating point, transition to the target operating
point, and a finish transition routine to either notify driver that
the clocks have scaled and operation of bus and DMA traffic may continue.

OpPoint draws the line about what's needed in the kernel a bit differently
than Matt's PowerOp code.  OpPoint only puts operating point support in
the kernel.  Polices for operting states and classes of operating states
are left to the power manager, in userland.  This simplifies the
kernel code, no string parsers for operating point parameter construction,
and makes it easier to customize a solution by customizing the power
manager.

A power manager is supplied with the OpPoint patch set as well.  I borrowed
the cpuspeed deamon and made a simple patch that uses the new OpPoint
sysfs interface.  The daemon can be compiled as the original cpuspeed or
oppointd deamon depending on the users choice.  The daemon provides the
same functions as the cpuspeed daemon.

OpPoint is a fully functional solution ready for testing and evaluation
in Andrew's or your tree.

The kernel patches are available at:

        http://source.mvista.com/~dsingleton/2.6.1-rc6

the power manager source code and patch is available at:

        http://source.mvista.com/~dsingleton/oppointd


David

Re: [linux-pm] cpufreq terminally broken [was Re: community PM requirements/issues and PowerOP]

[Vitaly Wool]

On 9/14/06, David Singleton <daviado@gmail.com> wrote:

> OpPoint constructs operating points for all supported frequency, voltage
> and suspend states for PC and SoC solutions running Linux.

...producing very hard-to-manage and long-to-search lists (did you
consider using trees for that BTW?)
Also, you'll have to maintain different lists for differemt
modifications of the same SoC. That will complicate the code prety
much.

> (The ARM pxa27x patch uses the cpufreq scaling routines to scale the LCD
> when frequencies are changed and works well when playing mpeg movies on
> the LCD during frequency scaling operations).

PXA is a hi-end stuff for embedded, so that might be not very illustrative.

> The Operating Points in OpPoint are simply created at compile time, in
> the same manner cpufreq tables are, and registered in
> /sys/power/operating_states directory when the cpu is identified at boot time.

So do you say there's no *kernel* interface to create OPs even?
Assume you've got a device which needs scaling and which driver may be
compiled as a module. Thus, you'll have to include OPs that reflect
this driver's clock scaling at the kernel compile time. Which is
nonsense in a way because the clock itself should be switched on
during probe() operation of the device driver.

> OpPoint draws the line about what's needed in the kernel a bit differently
> than Matt's PowerOp code.  OpPoint only puts operating point support in
> the kernel.  Polices for operting states and classes of operating states
> are left to the power manager, in userland.  This simplifies the
> kernel code, no string parsers for operating point parameter construction,
> and makes it easier to customize a solution by customizing the power
> manager.

That sounds nice :)

> OpPoint is a fully functional solution ready for testing and evaluation
> in Andrew's or your tree.

Can you please list the SoCs which this solution has been tested on?

Thanks,
   Vitaly

Re: cpufreq terminally broken [was Re: community PM requirements/issues and PowerOP]

[Vitaly Wool]

On 9/14/06, David Singleton <daviado@gmail.com> wrote:

> OpPoint constructs operating points for all supported frequency, voltage
> and suspend states for PC and SoC solutions running Linux.

...producing very hard-to-manage and long-to-search lists (did you
consider using trees for that BTW?)
Also, you'll have to maintain different lists for differemt
modifications of the same SoC. That will complicate the code prety
much.

> (The ARM pxa27x patch uses the cpufreq scaling routines to scale the LCD
> when frequencies are changed and works well when playing mpeg movies on
> the LCD during frequency scaling operations).

PXA is a hi-end stuff for embedded, so that might be not very illustrative.

> The Operating Points in OpPoint are simply created at compile time, in
> the same manner cpufreq tables are, and registered in
> /sys/power/operating_states directory when the cpu is identified at boot time.

So do you say there's no *kernel* interface to create OPs even?
Assume you've got a device which needs scaling and which driver may be
compiled as a module. Thus, you'll have to include OPs that reflect
this driver's clock scaling at the kernel compile time. Which is
nonsense in a way because the clock itself should be switched on
during probe() operation of the device driver.

> OpPoint draws the line about what's needed in the kernel a bit differently
> than Matt's PowerOp code.  OpPoint only puts operating point support in
> the kernel.  Polices for operting states and classes of operating states
> are left to the power manager, in userland.  This simplifies the
> kernel code, no string parsers for operating point parameter construction,
> and makes it easier to customize a solution by customizing the power
> manager.

That sounds nice :)

> OpPoint is a fully functional solution ready for testing and evaluation
> in Andrew's or your tree.

Can you please list the SoCs which this solution has been tested on?

Thanks,
   Vitaly

OpPoint summary

[Greg KH]

On Wed, Sep 13, 2006 at 04:50:43PM -0700, David Singleton wrote:
> Greg,
>   here's a few paragraphs about the power management code I'm working on.
> The OpPoint patch set is a fully functionaly power management solution,
> from kernel operating state support to userland power manager.

Thanks for the summary, but it was a bit longer than just "one
paragraph" :)

> OpPoint constructs operating points for all supported frequency, voltage
> and suspend states for PC and SoC solutions running Linux.  OpPoint
> does not break or replace cpufreq.  It leverages cpufreq code to provide
> the same driver scaling functions when cpu frequency changes affect drivers.

So it works with cpufreq?  That's a good thing, as it is a requirement.
We can't just break current usages.

> OpPoint is a fully functional solution ready for testing and evaluation
> in Andrew's or your tree.
> 
> The kernel patches are available at:
> 
>        http://source.mvista.com/~dsingleton/2.6.1-rc6

I get a 404 with that link :(

Care to resend your patches in the proper format, through email so that
we can see them, and possibly get some testing in -mm if they look sane?

thanks,

greg k-h

Re: [linux-pm] OpPoint summary

[Vitaly Wool]

Hi Greg,

On 9/14/06, Greg KH <greg@kroah.com> wrote:
> >
> > The kernel patches are available at:
> >
> >        http://source.mvista.com/~dsingleton/2.6.1-rc6
>
> I get a 404 with that link :(

I bet David meant http://source.mvista.com/~dsingleton/2.6.18-rc6/

Vitaly

Re: OpPoint summary

[Vitaly Wool]

Hi Greg,

On 9/14/06, Greg KH <greg@kroah.com> wrote:
> >
> > The kernel patches are available at:
> >
> >        http://source.mvista.com/~dsingleton/2.6.1-rc6
>
> I get a 404 with that link :(

I bet David meant http://source.mvista.com/~dsingleton/2.6.18-rc6/

Vitaly

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Pavel Machek]

Hi!

> > > Date: Mon, 11 Sep 2006 21:36:37 +0200
> > > From: Pavel Machek <pavel@ucw.cz>
> > >
> > > Kernel interface is not something to be experimented with.
> > 
> > Disagree.  How else to get it right??
> > Try, learn, improve.  That's experimentation.
> > Linux has no "stable API nonsense" ...
> > 
> > The point of "cathedral vs. bazaar" was that experimentation 
> > and evolution are more successful processes than "get it 
> > right the first time".
> ---
> 
> I think Pavel's point was that the userspace interface to 
> the kernel (at least the syscall interface) is stable (open to
> Extension by addition of syscalls, but closed to modification
> or deletion of existing and that any experimentation needs to 
> happen before functionality goes into the mainstream. 

Yes, that was my point. (And I'd add "plus you can't get around that
by introducing interface hidden by #ifdef").

> That said, I do think we probably need to add a new interface to
> cover operating points, because some of believe that policy needs
> to be in user space and the whole point of the OP abstraction is 
> that operating points are atomic. You can't just add knobs to
> control more factors, because all those knobs need to be turned
> at the same time. Setting an operating point is inherently an
> atomic operation, not n separate operations that can be taken
> serially.

Ok, "needs to be atomic" is first real argument for OP abstraction. I
wonder if we can get around that by delaying the transaction until
userspace tells us it made all the changes... otoh that is going to be
messy.

But do you have some reasonable way to integrate OP with cpufreq?

								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Vitaly Wool]

Hi,

On 9/14/06, Pavel Machek <pavel@ucw.cz> wrote:

> But do you have some reasonable way to integrate OP with cpufreq?

Do we really need to integrate OP with cpufreq at this point?

Vitaly

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Matthew Locke]

On Sep 14, 2006, at 2:12 AM, Pavel Machek wrote:

> Hi!
>
>>>> Date: Mon, 11 Sep 2006 21:36:37 +0200
>>>> From: Pavel Machek <pavel@ucw.cz>
>>>>
>>>> Kernel interface is not something to be experimented with.
>>>
>>> Disagree.  How else to get it right??
>>> Try, learn, improve.  That's experimentation.
>>> Linux has no "stable API nonsense" ...
>>>
>>> The point of "cathedral vs. bazaar" was that experimentation
>>> and evolution are more successful processes than "get it
>>> right the first time".
>> ---
>>
>> I think Pavel's point was that the userspace interface to
>> the kernel (at least the syscall interface) is stable (open to
>> Extension by addition of syscalls, but closed to modification
>> or deletion of existing and that any experimentation needs to
>> happen before functionality goes into the mainstream.
>
> Yes, that was my point. (And I'd add "plus you can't get around that
> by introducing interface hidden by #ifdef").
>
>> That said, I do think we probably need to add a new interface to
>> cover operating points, because some of believe that policy needs
>> to be in user space and the whole point of the OP abstraction is
>> that operating points are atomic. You can't just add knobs to
>> control more factors, because all those knobs need to be turned
>> at the same time. Setting an operating point is inherently an
>> atomic operation, not n separate operations that can be taken
>> serially.
>
> Ok, "needs to be atomic" is first real argument for OP abstraction. I
> wonder if we can get around that by delaying the transaction until
> userspace tells us it made all the changes... otoh that is going to be
> messy.
>
> But do you have some reasonable way to integrate OP with cpufreq?

Yes, it was presented in the PowerOP/cpufreq integration patches.  The 
cpufreq_driver layer is the natural integration point.

>
> 								Pavel
> -- 
> (english) http://www.livejournal.com/~pavelmachek
> (cesky, pictures) 
> http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
> _______________________________________________
> linux-pm mailing list
> linux-pm@lists.osdl.org
> https://lists.osdl.org/mailman/listinfo/linux-pm
>

PowerOP on lkml or linux-pm?

[Matthew Locke]

Pavel, Greg,

I started CC'ing lkml as you guys requested (well forced really).  Now 
we have half the discussion occurring on linux-pm and the other half on 
both.  The guys on lkml are going to be lost and even more confused 
than the people on this list.  If you guys want lkml to see the 
discussion, make sure you add them to the CC when replying to linux-pm 
only emails.

Perhaps we should keep the discussion on linux-pm until we are all 
straight and then send the results to lkml.  I'm open to whatever you 
want as along as we are consistent.

Matt

Re: PowerOP on lkml or linux-pm?

[Pavel Machek]

On Thu 2006-09-14 02:32:03, Matthew Locke wrote:
> Pavel, Greg,
> 
> I started CC'ing lkml as you guys requested (well forced really).  Now 
> we have half the discussion occurring on linux-pm and the other half on 
> both.  The guys on lkml are going to be lost and even more confused 
> than the people on this list.  If you guys want lkml to see the 
> discussion, make sure you add them to the CC when replying to linux-pm 
> only emails.

Yep, try to cc lkml on new threads, and keep ccs intact when
replying. That should be ok.

> Perhaps we should keep the discussion on linux-pm until we are all 
> straight and then send the results to lkml.  I'm open to whatever you 
> want as along as we are consistent.

No, we want lkml included in the discussion.
								Pavel

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Matthew Locke]

On Sep 14, 2006, at 2:12 AM, Pavel Machek wrote:

> Hi!
>
>>>> Date: Mon, 11 Sep 2006 21:36:37 +0200
>>>> From: Pavel Machek <pavel@ucw.cz>
>>>>
>>>> Kernel interface is not something to be experimented with.
>>>
>>> Disagree.  How else to get it right??
>>> Try, learn, improve.  That's experimentation.
>>> Linux has no "stable API nonsense" ...
>>>
>>> The point of "cathedral vs. bazaar" was that experimentation
>>> and evolution are more successful processes than "get it
>>> right the first time".
>> ---
>>
>> I think Pavel's point was that the userspace interface to
>> the kernel (at least the syscall interface) is stable (open to
>> Extension by addition of syscalls, but closed to modification
>> or deletion of existing and that any experimentation needs to
>> happen before functionality goes into the mainstream.
>
> Yes, that was my point. (And I'd add "plus you can't get around that
> by introducing interface hidden by #ifdef").
>
>> That said, I do think we probably need to add a new interface to
>> cover operating points, because some of believe that policy needs
>> to be in user space and the whole point of the OP abstraction is
>> that operating points are atomic. You can't just add knobs to
>> control more factors, because all those knobs need to be turned
>> at the same time. Setting an operating point is inherently an
>> atomic operation, not n separate operations that can be taken
>> serially.
>
> Ok, "needs to be atomic" is first real argument for OP abstraction. I
> wonder if we can get around that by delaying the transaction until
> userspace tells us it made all the changes... otoh that is going to be
> messy.
>
> But do you have some reasonable way to integrate OP with cpufreq?

Yes, it was presented in the PowerOP/cpufreq integration patches.  The 
cpufreq_driver layer is the natural integration point.

>
> 								Pavel
> -- 
> (english) http://www.livejournal.com/~pavelmachek
> (cesky, pictures) 
> http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
> _______________________________________________
> linux-pm mailing list
> linux-pm@lists.osdl.org
> https://lists.osdl.org/mailman/listinfo/linux-pm
>

Re: PowerOP on lkml or linux-pm?

[Matthew Locke]

On Sep 14, 2006, at 2:45 AM, Pavel Machek wrote:

> On Thu 2006-09-14 02:32:03, Matthew Locke wrote:
>> Pavel, Greg,
>>
>> I started CC'ing lkml as you guys requested (well forced really).  Now
>> we have half the discussion occurring on linux-pm and the other half 
>> on
>> both.  The guys on lkml are going to be lost and even more confused
>> than the people on this list.  If you guys want lkml to see the
>> discussion, make sure you add them to the CC when replying to linux-pm
>> only emails.
>
> Yep, try to cc lkml on new threads, and keep ccs intact when
> replying. That should be ok.

I don't understand why that would be ok.  lkml will miss key discussion 
in threads that don't include lkml required to understand the threads 
that include do lkml.  btw, isn't there some rule against cross posting 
like this?

>
>> Perhaps we should keep the discussion on linux-pm until we are all
>> straight and then send the results to lkml.  I'm open to whatever you
>> want as along as we are consistent.
>
> No, we want lkml included in the discussion.

Then you need to include lkml in the discussion not just random parts 
of the discussion.

> 								Pavel
>
> -- 
> (english) http://www.livejournal.com/~pavelmachek
> (cesky, pictures) 
> http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
>

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Eugeny S. Mints]

Matthew Locke wrote:
> On Sep 14, 2006, at 2:12 AM, Pavel Machek wrote:
> 
>> Hi!
>>
>>>>> Date: Mon, 11 Sep 2006 21:36:37 +0200
>>>>> From: Pavel Machek <pavel@ucw.cz>
>>>>>
>>>>> Kernel interface is not something to be experimented with.
>>>> Disagree.  How else to get it right??
>>>> Try, learn, improve.  That's experimentation.
>>>> Linux has no "stable API nonsense" ...
>>>>
>>>> The point of "cathedral vs. bazaar" was that experimentation
>>>> and evolution are more successful processes than "get it
>>>> right the first time".
>>> ---
>>>
>>> I think Pavel's point was that the userspace interface to
>>> the kernel (at least the syscall interface) is stable (open to
>>> Extension by addition of syscalls, but closed to modification
>>> or deletion of existing and that any experimentation needs to
>>> happen before functionality goes into the mainstream.
>> Yes, that was my point. (And I'd add "plus you can't get around that
>> by introducing interface hidden by #ifdef").
>>
>>> That said, I do think we probably need to add a new interface to
>>> cover operating points, because some of believe that policy needs
>>> to be in user space and the whole point of the OP abstraction is
>>> that operating points are atomic. You can't just add knobs to
>>> control more factors, because all those knobs need to be turned
>>> at the same time. Setting an operating point is inherently an
>>> atomic operation, not n separate operations that can be taken
>>> serially.
>> Ok, "needs to be atomic" is first real argument for OP abstraction. I
>> wonder if we can get around that by delaying the transaction until
>> userspace tells us it made all the changes... otoh that is going to be
>> messy.
>>
>> But do you have some reasonable way to integrate OP with cpufreq?
> 
> Yes, it was presented in the PowerOP/cpufreq integration patches.  The 
> cpufreq_driver layer is the natural integration point.
Exactly.

Separate or one universal user space<->kernel interface is another story. 
Universal is preferred of course and in two words to achieve universal interface 
current cpufreq interface needs to be improved - but remains unchanged for user 
space !!!! - in the way to handle "chose closet predefined frequency to an 
arbitrary freq value echo'ed into /sys/cpufreq/cpuN/freq" functionality in user 
space instead of in the kernel. Assuming that frequency attribute is exported 
for all available operating points it is possible to implement the "cpufreq 
frequency selection logic" in user space and having such functionality in the 
kernel just violates the main rule of having everything possible outside of the 
kernel.

More details here:
http://lists.osdl.org/pipermail/linux-pm/2006-September/003660.html
and here
http://lists.osdl.org/pipermail/linux-pm/2006-September/003671.html

Paval, plz NOTE, that  you don't have lkml in CC on this thread and I personally 
feel that you've brought a really terrible confusion to everyone with your lkml 
step. I'm wondering whether you are braking "no cross postings" rule as well.....

Eugeny
> 
>> 								Pavel
>> -- 
>> (english) http://www.livejournal.com/~pavelmachek
>> (cesky, pictures) 
>> http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
>> _______________________________________________
>> linux-pm mailing list
>> linux-pm@lists.osdl.org
>> https://lists.osdl.org/mailman/listinfo/linux-pm
>>
> 
> _______________________________________________
> linux-pm mailing list
> linux-pm@lists.osdl.org
> https://lists.osdl.org/mailman/listinfo/linux-pm
> 

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Pavel Machek]

Hi!

> operating points it is possible to implement the "cpufreq frequency 
> selection logic" in user space and having such functionality in the kernel 
> just violates the main rule of having everything possible outside of the 
> kernel.

You got the rules wrong. "Keep the code out of kernel" is important
rule, but probably not the main one.

> Paval, plz NOTE, that  you don't have lkml in CC on this thread and I 
> personally feel that you've brought a really terrible confusion to everyone 
> with your lkml step. I'm wondering whether you are braking "no cross 
> postings" rule as well.....

Cc-ing lkml is considered okay.

Anyway, please do _proper_ submission, cc-ing lkml, explaining why it
is needed so that me and lkml actually know what is going on. Include
those "elevator pitches".
									Pavel

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: [linux-pm] community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Eugeny S. Mints]

Pavel Machek wrote:
> Hi!
> 
>> operating points it is possible to implement the "cpufreq frequency 
>> selection logic" in user space and having such functionality in the kernel 
>> just violates the main rule of having everything possible outside of the 
>> kernel.
> 
> You got the rules wrong. "Keep the code out of kernel" is important
> rule, but probably not the main one.
funny. not to mention that it was not the only argument I presented but please 
tell us explicitly what's your reason to blow out kernel footprint by the code 
which can be handled outside the kernel. I'd prefer to see technical reasons a 
kind of latencies, etc but not  the constant refrain "don't touch cpufreq 
interface". Especially considering that proposed improvements _do_ _not_ 
_change_ the interface.

And just FYI kernel footprint was stated as one of main current issues at least 
on the last OLS.
> 
>> Paval, plz NOTE, that  you don't have lkml in CC on this thread and I 
>> personally feel that you've brought a really terrible confusion to everyone 
>> with your lkml step. I'm wondering whether you are braking "no cross 
>> postings" rule as well.....
> 
> Cc-ing lkml is considered okay.
> 
> Anyway, please do _proper_ submission, 
I already did _proper_ submissions several time on IMO the _proper_ list.
>cc-ing lkml, explaining why it
> is needed so that me and lkml actually know what is going on. 
will do

Eugeny
>Include
> those "elevator pitches".
> 									Pavel
> 

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Eugeny S. Mints]

Pavel Machek wrote:
> Hi!
> 
>> operating points it is possible to implement the "cpufreq frequency 
>> selection logic" in user space and having such functionality in the kernel 
>> just violates the main rule of having everything possible outside of the 
>> kernel.
> 
> You got the rules wrong. "Keep the code out of kernel" is important
> rule, but probably not the main one.
funny. not to mention that it was not the only argument I presented but please 
tell us explicitly what's your reason to blow out kernel footprint by the code 
which can be handled outside the kernel. I'd prefer to see technical reasons a 
kind of latencies, etc but not  the constant refrain "don't touch cpufreq 
interface". Especially considering that proposed improvements _do_ _not_ 
_change_ the interface.

And just FYI kernel footprint was stated as one of main current issues at least 
on the last OLS.
> 
>> Paval, plz NOTE, that  you don't have lkml in CC on this thread and I 
>> personally feel that you've brought a really terrible confusion to everyone 
>> with your lkml step. I'm wondering whether you are braking "no cross 
>> postings" rule as well.....
> 
> Cc-ing lkml is considered okay.
> 
> Anyway, please do _proper_ submission, 
I already did _proper_ submissions several time on IMO the _proper_ list.
>cc-ing lkml, explaining why it
> is needed so that me and lkml actually know what is going on. 
will do

Eugeny
>Include
> those "elevator pitches".
> 									Pavel
> 

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Vitaly Wool]

Eugeny,

On 9/14/06, Eugeny S. Mints <eugeny.mints@gmail.com> wrote:

> Separate or one universal user space<->kernel interface is another story.
> Universal is preferred of course and in two words to achieve universal interface
> current cpufreq interface needs to be improved - but remains unchanged for user
> space !!!! - in the way to handle "chose closet predefined frequency to an
> arbitrary freq value echo'ed into /sys/cpufreq/cpuN/freq" functionality in user
> space instead of in the kernel. Assuming that frequency attribute is exported
> for all available operating points it is possible to implement the "cpufreq
> frequency selection logic" in user space and having such functionality in the
> kernel just violates the main rule of having everything possible outside of the
> kernel.

Let's not be in a hurry, if possible.
I wonder why not to present PowerOP with a _separate_ *kernel* API at
the moment.

> More details here:
> http://lists.osdl.org/pipermail/linux-pm/2006-September/003660.html
> and here
> http://lists.osdl.org/pipermail/linux-pm/2006-September/003671.html

Again, let's first make PowerOP accepted in mainline and then start
talking about integration with cpufreq.
Looking again at the links you've provided, I'd guess BTW that you
meant configfs not sysfs in some cases.

Vitaly

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Vitaly Wool]

Pavel,

On 9/14/06, Pavel Machek <pavel@ucw.cz> wrote:
> Hi!
>
> > operating points it is possible to implement the "cpufreq frequency
> > selection logic" in user space and having such functionality in the kernel
> > just violates the main rule of having everything possible outside of the
> > kernel.
>
> You got the rules wrong. "Keep the code out of kernel" is important
> rule, but probably not the main one.

from aside, it looks like you're choosing 'rules' and assign then
'priorities' in a too arbitrary way which is by a strange accident
fits your point of view best of all.
May I remind you that Linux world is not only laptops and Sharp Zaurus? ;)

Thanks,
   Vitaly

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Eugeny S. Mints]

Vitaly,

Vitaly Wool wrote:
> Eugeny,
> 
> On 9/14/06, Eugeny S. Mints <eugeny.mints@gmail.com> wrote:
> 
>> Separate or one universal user space<->kernel interface is another story.
>> Universal is preferred of course and in two words to achieve universal 
>> interface
>> current cpufreq interface needs to be improved - but remains unchanged 
>> for user
>> space !!!! - in the way to handle "chose closet predefined frequency 
>> to an
>> arbitrary freq value echo'ed into /sys/cpufreq/cpuN/freq" 
>> functionality in user
>> space instead of in the kernel. Assuming that frequency attribute is 
>> exported
>> for all available operating points it is possible to implement the 
>> "cpufreq
>> frequency selection logic" in user space and having such functionality 
>> in the
>> kernel just violates the main rule of having everything possible 
>> outside of the
>> kernel.
> 
> Let's not be in a hurry, if possible.
> I wonder why not to present PowerOP with a _separate_ *kernel* API at
> the moment.
it is exactly how PowerOP submission is positioned - it was submitted as a 
standalone patch without any relationship to cpufreq integration patch.

Cpufreq patch was submitted mostly for reference and discussion; to demonstrate 
that future integration with cpufreq is in mind and outline that PowerOP will 
not require cpufreq _interface_ to be changed.
> 
>> More details here:
>> http://lists.osdl.org/pipermail/linux-pm/2006-September/003660.html
>> and here
>> http://lists.osdl.org/pipermail/linux-pm/2006-September/003671.html
> 
> Again, let's first make PowerOP accepted in mainline and then start
> talking about integration with cpufreq.

that's exactly our understanding of an evolutionary development process.

> Looking again at the links you've provided, I'd guess BTW that you
> meant configfs not sysfs in some cases.
configfs is in my TODO list.

	Eugeny
> 
> Vitaly
> 

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Pavel Machek]

> Pavel,

> > > operating points it is possible to implement the "cpufreq frequency
> > > selection logic" in user space and having such functionality in the kernel
> > > just violates the main rule of having everything possible outside of the
> > > kernel.
> >
> > You got the rules wrong. "Keep the code out of kernel" is important
> > rule, but probably not the main one.
> 
> from aside, it looks like you're choosing 'rules' and assign then
> 'priorities' in a too arbitrary way which is by a strange accident
> fits your point of view best of all.
> May I remind you that Linux world is not only laptops and Sharp Zaurus? ;)

Actually, laptops and zauruses seem to be the only "interesting"
machines from pm perspective. Then there are Motorola cellphones, but
Motorola tried hard not to enable users changing kernel... so they are
irrelevant.
								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Pavel Machek]

On Thu 2006-09-14 15:03:11, Pavel Machek wrote:
> 
> > Pavel,
> 
> > > > operating points it is possible to implement the "cpufreq frequency
> > > > selection logic" in user space and having such functionality in the kernel
> > > > just violates the main rule of having everything possible outside of the
> > > > kernel.
> > >
> > > You got the rules wrong. "Keep the code out of kernel" is important
> > > rule, but probably not the main one.
> > 
> > from aside, it looks like you're choosing 'rules' and assign then
> > 'priorities' in a too arbitrary way which is by a strange accident
> > fits your point of view best of all.
> > May I remind you that Linux world is not only laptops and Sharp Zaurus? ;)
> 
> Actually, laptops and zauruses seem to be the only "interesting"
> machines from pm perspective. Then there are Motorola cellphones, but
> Motorola tried hard not to enable users changing kernel... so they are
> irrelevant.

Make that "mostly irrelevant"... as community will find a way to flash
them, eventually. Still 2.6-based machine with more advanced power
management would be nice. AFAICT zaurus are best machines today...
								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Vitaly Wool]

Pavel,

On 9/14/06, Pavel Machek <pavel@ucw.cz> wrote:
>
> > Pavel,
>
> > > > operating points it is possible to implement the "cpufreq frequency
> > > > selection logic" in user space and having such functionality in the kernel
> > > > just violates the main rule of having everything possible outside of the
> > > > kernel.
> > >
> > > You got the rules wrong. "Keep the code out of kernel" is important
> > > rule, but probably not the main one.
> >
> > from aside, it looks like you're choosing 'rules' and assign then
> > 'priorities' in a too arbitrary way which is by a strange accident
> > fits your point of view best of all.
> > May I remind you that Linux world is not only laptops and Sharp Zaurus? ;)
>
> Actually, laptops and zauruses seem to be the only "interesting"
> machines from pm perspective. Then there are Motorola cellphones, but
> Motorola tried hard not to enable users changing kernel... so they are
> irrelevant.

Well, I never said Zaurus was no good :)
Please don't forget about Nokia 770 and its possible follow-ups.
Also, please keep in mind that if we come to a joint PM solution that
is in mainline, Motorola will use it... and will be contributing
changes back to the community. If there was a PM solution adopted in
mainline which fit the needs of embedded devices, more vendors would
turn to using Linux.
I. e., what prevents Sharp from making a open-code Lnux-based cell
phone? I do think that the absense of PM framework suitable for
embedded is one of the main engineering reasons... So let us broaden
our views and work together :)

Vitaly

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Pavel Machek]

Hi!

> >> from aside, it looks like you're choosing 'rules' and assign then
> >> 'priorities' in a too arbitrary way which is by a strange accident
> >> fits your point of view best of all.
> >> May I remind you that Linux world is not only laptops and Sharp Zaurus? 
> >;)
> >
> >Actually, laptops and zauruses seem to be the only "interesting"
> >machines from pm perspective. Then there are Motorola cellphones, but
> >Motorola tried hard not to enable users changing kernel... so they are
> >irrelevant.
> 
> Well, I never said Zaurus was no good :)
> Please don't forget about Nokia 770 and its possible follow-ups.

Well, for now, Nokia 770 is zaurus with wifi but without keyboard
(mostly). It seems to be very similar to zaurus pm-wise.

								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Vitaly Wool]

On 9/14/06, Pavel Machek <pavel@suse.cz> wrote:

> Well, for now, Nokia 770 is zaurus with wifi but without keyboard
> (mostly). It seems to be very similar to zaurus pm-wise.

Yea, but AFAIK from FOSDEM/OLS Nokia folks are not satisfied with that
and would like to have a more comprehensive PM framework... like
PowerOP, for instance :)
That's my impression.

Vitaly

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[David Brownell]

> > May I remind you that Linux world is not only laptops and Sharp Zaurus? ;)
>
> Actually, laptops and zauruses seem to be the only "interesting"
> machines from pm perspective. Then there are Motorola cellphones, but
> Motorola tried hard not to enable users changing kernel... so they are
> irrelevant.

Get yourself some OMAP hardware then; your blinders are way too effective!

OMAP1 hardware is easily had; an OSK, or a Nokia N770.  The latter is
battery powered already, without the hardware mods...

- Dave

Re: cpufreq terminally broken [was Re: community PM requirements/issues and PowerOP]

[Mark Gross]

On Tue, Sep 12, 2006 at 10:33:28AM +0200, Pavel Machek wrote:
> Hi!
> 
> > > > >No, there is reason to keep that in kernel -- so that cpufreq
> > > > >userspace interface can be kept, and so that resulting kernel<->user
> > > > >interface is not ugly.
> > > > Cpuferq defines cpufreq_frequency_table structure in arch independent 
> > > > header while it's arch dependent data structure. A lot of code is built 
> > > > around this invalid basic brick and therefore is invalid: cpufreq tables, 
> > > > interface with cpu freq drivers, etc. Notion of transition latency as it 
> > > > defined by cpufreq is wrong because it's not a function of cpu type but 
> > > > function of current and next operating point. no runtime control on 
> > > > operating points set. it's always the same set of operating points for all 
> > > > system cpus in smp case and no way to define different sets or track any 
> > > > dependencies in case say multi core cpus. insufficient kernel<->user space 
> > > > interface to handle embedded requirements and no way to extend it within 
> > > > current design. Shall I continue?  Why should then anyone want to keep 
> > > > cpufreq userspace interface just due to keep it?
> > > 
> > > Yes, please continue. I do not think we can just rip cpufreq interface
> > > out of kernel, and I do not think it is as broken as you claim it
> > > is. Ripping interface out of kernel takes years.
> > > 
> > > I'm sure cpufreq_frequency_table could be moved to asm/ header if you
> > > felt strongly about that.
> > > 
> > > I believe we need to fix cpufreq if it is broken for embedded
> > > cases.
> > 
> > cpufreq is broken at the cpufreq_driver interface for embedded
> > applications needing control over more than one control variable at a
> > time.
> > 
> > That interface only supports setting target frequencies, and expanding it
> > to set target frequencies and voltages is not possible without something
> > like PowerOP.  Adding the types of parameters to cpufreq would likely
> > make cpufreq a mess.
> 
> Can we at least try adding that, before deciding cpufreq is unsuitable
> and starting new interface? I do not think issues are nearly as big as
> you think.. (at user<->kernel interface level, anyway; you'll need big
> changes under the hood).

We are trying.  The PowerOP patches from Matt and Eugeny start to put
into place some of the kernel mode plumbing for this in a way that
avoids thrashing the existing models, and it addresses the needs of the
operating point PM community.  Which is large in the CE and Embedded
camps.

--mgross

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[David Brownell]

> Well, for now, Nokia 770 is zaurus with wifi but without keyboard
> (mostly). It seems to be very similar to zaurus pm-wise.

Not hardly.  I suggest you _start_ by looking at the clock tree
specs for the OMAP5912 (very similar to the OMAP1710 in N770) ...

Re: [linux-pm] cpufreq terminally broken [was Re: community PM requirements/issues and PowerOP]

[Mark Gross]

On Tue, Sep 12, 2006 at 01:10:24PM +0400, Vitaly Wool wrote:
> Pavel,
> 
> On 9/12/06, Pavel Machek <pavel@ucw.cz> wrote:
> >Can we at least try adding that, before deciding cpufreq is unsuitable
> >and starting new interface? I do not think issues are nearly as big as
> >you think.. (at user<->kernel interface level, anyway; you'll need big
> >changes under the hood).
> 
> who talks about user <-> kernel interface level changes at the moment?!
>

Mostly Pavel is.

There are questions on how to set/get operating points between the
platform and user space, and some questions on one to make the space of
operating points extensible outside of compile time deployment nice.
But these questions aren't the ones I see folks fussing about.

--mgross

Re: cpufreq terminally broken [was Re: community PM requirements/issues and PowerOP]

[Mark Gross]

On Tue, Sep 12, 2006 at 01:10:24PM +0400, Vitaly Wool wrote:
> Pavel,
> 
> On 9/12/06, Pavel Machek <pavel@ucw.cz> wrote:
> >Can we at least try adding that, before deciding cpufreq is unsuitable
> >and starting new interface? I do not think issues are nearly as big as
> >you think.. (at user<->kernel interface level, anyway; you'll need big
> >changes under the hood).
> 
> who talks about user <-> kernel interface level changes at the moment?!
>

Mostly Pavel is.

There are questions on how to set/get operating points between the
platform and user space, and some questions on one to make the space of
operating points extensible outside of compile time deployment nice.
But these questions aren't the ones I see folks fussing about.

--mgross

Re: cpufreq user<->kernel interface removal [was Re: community PM requirements/issues and PowerOP]

[Mark Gross]

On Mon, Sep 11, 2006 at 08:35:37PM -0700, Greg KH wrote:
> On Mon, Sep 11, 2006 at 04:50:25PM -0700, Mark Gross wrote:
> > The PowerOP patch has nothing to do with the removal of cpufreq.  You
> > may be confusing this work with the david signleton patch.
> 
> I am totally confused about who is working on what, and what provides
> what.
> 
> Can someone make  quick cheat-sheet that shows the different
> developers/companies and projects here?  The fact that it's impossible
> to keep this straight in the first place does not bode well...

Power-OP: Matt, Eugeny, Igor, myself to a much lesser extent
Oppoint: David

Interested parties to getting operating point concepts into the main
line kernel are CELF and MLI members.

> 
> Or, can each of the different projects send a _short_, 1 paragraph, 4
> sentance maximum summary of the different things.  Think of it as your
> "elevator pitch".  The different multi-page summaries ware making my
> eyes glaze over...
> 

CE and embedded Linux users have not been able to use cpufreq, mostly
because those platforms don't have ACPI like FW for controlling all the
power parameters NOT exposed on PC's and laptops, where the PM control
possibilities are much more exposed to the OS requiring OS support to
leverage.

The notion of operating point has become very popular in the CE
/embedded space.  Some variant of it is used in every CE device and
there is a need to get some common way to tickle the platform PM for non
PC hardware.

PowerOP is the derived from Operating Point interface portion of the DPM
and is an attempt to provide a common way for this.  It started life as
a patch that came out about 1 year ago by Todd Poyner.  This version of
PowerOP has been a collaboration of a group of folks that got together
at the PM-Summit last April.

Oppoint is also derived from the interface portion of DPM but goes
farther to include more of DPM, causes confusion and controversy and was
pushed at a bad time.  It would be nice if the Oppoint patch be
re-submitted as a patch to the PowerOP patch once it gets some traction
in the MM tree.


> thanks,
> 
> greg k-h

Re: OpPoint summary

[David Singleton]

On 9/13/06, Greg KH <greg@kroah.com> wrote:
> On Wed, Sep 13, 2006 at 04:50:43PM -0700, David Singleton wrote:
> > Greg,
> >   here's a few paragraphs about the power management code I'm working on.
> > The OpPoint patch set is a fully functionaly power management solution,
> > from kernel operating state support to userland power manager.
>
> Thanks for the summary, but it was a bit longer than just "one
> paragraph" :)
>
> > OpPoint constructs operating points for all supported frequency, voltage
> > and suspend states for PC and SoC solutions running Linux.  OpPoint
> > does not break or replace cpufreq.  It leverages cpufreq code to provide
> > the same driver scaling functions when cpu frequency changes affect drivers.
>
> So it works with cpufreq?  That's a good thing, as it is a requirement.
> We can't just break current usages.
>
> > OpPoint is a fully functional solution ready for testing and evaluation
> > in Andrew's or your tree.
> >
> > The kernel patches are available at:
> >
> >        http://source.mvista.com/~dsingleton/2.6.1-rc6
>
> I get a 404 with that link :(
>
> Care to resend your patches in the proper format, through email so that
> we can see them, and possibly get some testing in -mm if they look sane?

Whoops, there are in the 2.6.18-rc6 directory.  Here's the core patch inlined:


Signed-Off-by: David Singleton <dsingleton@mvista.com>

 drivers/base/driver.c        |    1
 drivers/base/power/Makefile  |    2
 drivers/base/power/oppoint.c |   74 +++++++++
 include/linux/pm.h           |   34 ++++
 kernel/power/main.c          |  328 +++++++++++++++++++++++++++++++++++++------
 kernel/power/power.h         |    2
 6 files changed, 397 insertions(+), 44 deletions(-)

Index: linux-2.6.17/kernel/power/main.c
===================================================================
--- linux-2.6.17.orig/kernel/power/main.c
+++ linux-2.6.17/kernel/power/main.c
@@ -16,6 +16,7 @@
 #include <linux/init.h>
 #include <linux/pm.h>
 #include <linux/console.h>
+#include <linux/module.h>

 #include "power.h"

@@ -49,7 +50,7 @@ void pm_set_ops(struct pm_ops * ops)
  *     the platform can enter the requested state.
  */

-static int suspend_prepare(suspend_state_t state)
+static int suspend_prepare(struct oppoint * state)
 {
        int error = 0;
        unsigned int free_pages;
@@ -82,7 +83,7 @@ static int suspend_prepare(suspend_state
        }

        if (pm_ops->prepare) {
-               if ((error = pm_ops->prepare(state)))
+               if ((error = pm_ops->prepare(state->type)))
                        goto Thaw;
        }

@@ -94,7 +95,7 @@ static int suspend_prepare(suspend_state
        return 0;
  Finish:
        if (pm_ops->finish)
-               pm_ops->finish(state);
+               pm_ops->finish(state->type);
  Thaw:
        thaw_processes();
  Enable_cpu:
@@ -104,7 +105,7 @@ static int suspend_prepare(suspend_state
 }


-int suspend_enter(suspend_state_t state)
+int suspend_enter(struct oppoint * state)
 {
        int error = 0;
        unsigned long flags;
@@ -115,7 +116,7 @@ int suspend_enter(suspend_state_t state)
                printk(KERN_ERR "Some devices failed to power down\n");
                goto Done;
        }
-       error = pm_ops->enter(state);
+       error = pm_ops->enter(state->type);
        device_power_up();
  Done:
        local_irq_restore(flags);
@@ -131,36 +132,98 @@ int suspend_enter(suspend_state_t state)
  *     console that we've allocated. This is not called for suspend-to-disk.
  */

-static void suspend_finish(suspend_state_t state)
+static void suspend_finish(struct oppoint * state)
 {
        device_resume();
        resume_console();
        thaw_processes();
        enable_nonboot_cpus();
        if (pm_ops && pm_ops->finish)
-               pm_ops->finish(state);
+               pm_ops->finish(state->type);
        pm_restore_console();
 }


+struct oppoint *current_state;
+struct oppoint pm_states = {
+       .name = "default",
+       .type = PM_SUSPEND_ON,
+};
+
+static struct oppoint standby = {
+       .name = "standby",
+       .type = PM_SUSPEND_STANDBY,
+};
+struct oppoint *oppoint_standby;

+static struct oppoint mem = {
+       .name = "mem",
+       .type = PM_SUSPEND_MEM,
+       .frequency = 0,
+       .voltage = 0,
+       .latency = 150,
+};
+struct oppoint *oppoint_mem;

-static const char * const pm_states[PM_SUSPEND_MAX] = {
-       [PM_SUSPEND_STANDBY]    = "standby",
-       [PM_SUSPEND_MEM]        = "mem",
 #ifdef CONFIG_SOFTWARE_SUSPEND
-       [PM_SUSPEND_DISK]       = "disk",
-#endif
+struct oppoint disk = {
+       .name = "disk",
+       .type = PM_SUSPEND_DISK,
 };
+#endif

-static inline int valid_state(suspend_state_t state)
+/*
+ *
+ */
+static int pm_change_state(struct oppoint *state)
+{
+       int error = 0;
+
+       printk("OpPoint: changing from %s to %s\n", current_state->name,
+            state->name);
+       /*
+        * compare to current operating point.
+        * if different change to new operating point.
+        */
+       if (current_state == state)
+               goto out;
+
+       /*
+        * prepare_transition does device constraint checking.  If
+        * a new operating point will put a device in an unsupported
+        * state, lcd clock too low, NIC bus too low, etc.  the new state
+        * cannot be entered (until the constrainded device is suspended).
+        * If prepare_transition fails we don't go to the new operating
+        * point.
+        */
+       if ((error = state->prepare_transition(current_state, state)))
+               goto out;
+
+       /*
+        * if the transition fails we call the finish transistion
+        * with the current state as the new state, causing
+        * the finish to return to the current_state.
+        */
+
+       if ((error = state->transition(current_state, state)))
+               state = current_state;
+
+       if ((state->finish_transition(current_state, state)) == 0)
+               current_state = state;
+
+out:
+       printk("OpPoint: State change returned %d\n", error);
+       return error;
+}
+
+static inline int valid_state(struct oppoint * state)
 {
        /* Suspend-to-disk does not really need low-level support.
         * It can work with reboot if needed. */
-       if (state == PM_SUSPEND_DISK)
+       if (state->type == PM_SUSPEND_DISK)
                return 1;

-       if (pm_ops && pm_ops->valid && !pm_ops->valid(state))
+       if (pm_ops && pm_ops->valid && !pm_ops->valid(state->type))
                return 0;
        return 1;
 }
@@ -168,7 +231,7 @@ static inline int valid_state(suspend_st

 /**
  *     enter_state - Do common work of entering low-power state.
- *     @state:         pm_state structure for state we're entering.
+ *     @state:         oppoint structure for state we're entering.
  *
  *     Make sure we're the only ones trying to enter a sleep state. Fail
  *     if someone has beat us to it, since we don't want anything weird to
@@ -177,7 +240,7 @@ static inline int valid_state(suspend_st
  *     we've woken up).
  */

-static int enter_state(suspend_state_t state)
+static int enter_state(struct oppoint *state)
 {
        int error;

@@ -186,16 +249,21 @@ static int enter_state(suspend_state_t s
        if (down_trylock(&pm_sem))
                return -EBUSY;

-       if (state == PM_SUSPEND_DISK) {
+       if (state->type == PM_SUSPEND_DISK) {
                error = pm_suspend_disk();
                goto Unlock;
        }

-       pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
+       if (state->type == PM_FREQ_CHANGE || state->type == PM_VOLT_CHANGE) {
+               error = pm_change_state(state);
+               goto Unlock;
+       }
+
+       pr_debug("PM: Preparing system for %s sleep\n", state->name);
        if ((error = suspend_prepare(state)))
                goto Unlock;

-       pr_debug("PM: Entering %s sleep\n", pm_states[state]);
+       pr_debug("PM: Entering %s sleep\n", state->name);
        error = suspend_enter(state);

        pr_debug("PM: Finishing wakeup.\n");
@@ -211,7 +279,15 @@ static int enter_state(suspend_state_t s
  */
 int software_suspend(void)
 {
-       return enter_state(PM_SUSPEND_DISK);
+       struct oppoint *this, *next;
+       struct list_head *head = &pm_states.list;
+       int error = 0;
+
+       list_for_each_entry_safe(this, next, head, list) {
+               if (this->type == PM_SUSPEND_DISK)
+                       error= enter_state(this);
+       }
+       return error;
 }


@@ -223,9 +299,9 @@ int software_suspend(void)
  *     structure, and enter (above).
  */

-int pm_suspend(suspend_state_t state)
+int pm_suspend(struct oppoint * state)
 {
-       if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
+       if (state->type > PM_SUSPEND_ON && state->type <= PM_SUSPEND_MAX)
                return enter_state(state);
        return -EINVAL;
 }
@@ -248,36 +324,29 @@ decl_subsys(power,NULL,NULL);

 static ssize_t state_show(struct subsystem * subsys, char * buf)
 {
-       int i;
        char * s = buf;

-       for (i = 0; i < PM_SUSPEND_MAX; i++) {
-               if (pm_states[i] && valid_state(i))
-                       s += sprintf(s,"%s ", pm_states[i]);
-       }
-       s += sprintf(s,"\n");
+       s += sprintf(s,"%s\n", current_state->name);
        return (s - buf);
 }

 static ssize_t state_store(struct subsystem * subsys, const char *
buf, size_t n)
 {
-       suspend_state_t state = PM_SUSPEND_STANDBY;
-       const char * const *s;
+       struct oppoint *this, *next;
+       struct list_head *head = &pm_states.list;
        char *p;
-       int error;
+       int error = -EINVAL;
        int len;

        p = memchr(buf, '\n', n);
        len = p ? p - buf : n;
-
-       for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
-               if (*s && !strncmp(buf, *s, len))
+       list_for_each_entry_safe(this, next, head, list) {
+               if ((strlen(this->name) == len) &&
+                  (!strncmp(this->name, buf, len))) {
+                       error = enter_state(this);
                        break;
+               }
        }
-       if (state < PM_SUSPEND_MAX && *s)
-               error = enter_state(state);
-       else
-               error = -EINVAL;
        return error ? error : n;
 }

@@ -292,12 +361,191 @@ static struct attribute_group attr_group
        .attrs = g,
 };

+static struct kobject oppoint_kobj = {
+        .kset = &power_subsys.kset,
+};
+
+struct oppoint_attribute {
+        struct attribute        attr;
+        ssize_t (*show)(struct kobject * kobj, char * buf);
+        ssize_t (*store)(struct kobject * kobj, const char * buf,
size_t count);
+};
+
+#define to_oppoint(obj) container_of(obj,struct oppoint,kobj)
+#define to_oppoint_attr(_attr) container_of(_attr,struct
oppoint_attribute,attr)
+/*
+ * the frequency, voltage and latency files are readonly
+ */
+
+static ssize_t oppoint_voltage_show(struct kobject * kobj, char * buf)
+{
+       ssize_t len;
+       struct oppoint *opt = to_oppoint(kobj);
+
+       len = sprintf(buf, "%8d\n", opt->voltage);
+
+       return len;
+}
+
+static ssize_t oppoint_voltage_store(struct kobject * kobj, const char * buf,
+       size_t n)
+{
+        return -EINVAL;
+
+}
+
+static ssize_t oppoint_frequency_show(struct kobject * kobj, char * buf)
+{
+       ssize_t len;
+       struct oppoint *opt = to_oppoint(kobj);
+
+       len = sprintf(buf, "%8d\n", opt->frequency);
+
+       return len;
+}
+
+static ssize_t oppoint_frequency_store(struct kobject * kobj,
+        const char * buf, size_t n)
+{
+        return -EINVAL;
+
+}
+
+static ssize_t oppoint_latency_show(struct kobject * kobj, char * buf)
+{
+       ssize_t len;
+       struct oppoint *opt = to_oppoint(kobj);
+
+       len = sprintf(buf, "%8d\n", opt->latency);
+
+       return len;
+}
+
+static ssize_t oppoint_latency_store(struct kobject * kobj,
+        const char * buf, size_t n)
+{
+        return -EINVAL;
+
+}
+
+static struct oppoint_attribute frequency_attr = {
+        .attr   = {
+                .name = "frequency",
+                .mode = 0400,
+        },
+        .show   = oppoint_frequency_show,
+        .store  = oppoint_frequency_store,
+};
+
+static struct oppoint_attribute voltage_attr = {
+        .attr   = {
+                .name = "voltage",
+                .mode = 0400,
+        },
+        .show   = oppoint_voltage_show,
+        .store  = oppoint_voltage_store,
+};
+
+static struct oppoint_attribute latency_attr = {
+        .attr   = {
+                .name = "latency",
+                .mode = 0400,
+        },
+        .show   = oppoint_latency_show,
+        .store  = oppoint_latency_store,
+};
+
+static ssize_t
+oppoint_attr_show(struct kobject * kobj, struct attribute * attr, char * buf)
+{
+       struct oppoint_attribute * opt_attr = to_oppoint_attr(attr);
+       ssize_t ret = 0;
+
+       if (opt_attr->show)
+               ret = opt_attr->show(kobj,buf);
+       return ret;
+}
+
+static ssize_t
+oppoint_attr_store(struct kobject * kobj, struct attribute * attr,
+             const char * buf, size_t count)
+{
+       return -EINVAL;
+}
+
+static void oppoint_kobj_release(struct kobject *kobj)
+{
+       return;
+}
+
+static struct sysfs_ops oppoint_sysfs_ops = {
+       .show   = oppoint_attr_show,
+       .store  = oppoint_attr_store,
+};
+
+static struct attribute * oppoint_default_attrs[] = {
+       &frequency_attr.attr,
+       &voltage_attr.attr,
+       &latency_attr.attr,
+       NULL,
+};
+
+static struct kobj_type ktype_operating_point = {
+        .release        = oppoint_kobj_release,
+        .sysfs_ops      = &oppoint_sysfs_ops,
+        .default_attrs  = oppoint_default_attrs,
+};
+
+int unregister_operating_point(struct oppoint *opt)
+{
+       down(&pm_sem);
+       list_del_init(&opt->list);
+       sysfs_remove_file(&opt->kobj, &frequency_attr.attr);
+       sysfs_remove_file(&opt->kobj, &voltage_attr.attr);
+       sysfs_remove_file(&opt->kobj, &latency_attr.attr);
+       up(&pm_sem);
+}
+EXPORT_SYMBOL(unregister_operating_point);
+
+int register_operating_point(struct oppoint *opt)
+{
+       down(&pm_sem);
+       kobject_set_name(&opt->kobj, opt->name);
+       opt->kobj.kset = &power_subsys.kset;
+       opt->kobj.parent = &oppoint_kobj;
+       opt->kobj.ktype = &ktype_operating_point;
+       kobject_register(&opt->kobj);
+
+       sysfs_create_file(&opt->kobj, &frequency_attr.attr);
+       sysfs_create_file(&opt->kobj, &voltage_attr.attr);
+       sysfs_create_file(&opt->kobj, &latency_attr.attr);
+
+       list_add_tail(&opt->list, &pm_states.list);
+       up(&pm_sem);
+       return 0;
+}
+EXPORT_SYMBOL(register_operating_point);

 static int __init pm_init(void)
 {
+
        int error = subsystem_register(&power_subsys);
-       if (!error)
+       if (!error) {
                error = sysfs_create_group(&power_subsys.kset.kobj,&attr_group);
+               kobject_set_name(&oppoint_kobj, "operating_points");
+               kobject_register(&oppoint_kobj);
+       }
+
+
+       INIT_LIST_HEAD(&pm_states.list);
+
+#ifdef CONFIG_SOFTWARE_SUSPEND
+       register_operating_point(&disk);
+#endif
+       register_operating_point(&mem);
+       register_operating_point(&standby);
+       current_state = &pm_states;
+
        return error;
 }

Index: linux-2.6.17/include/linux/pm.h
===================================================================
--- linux-2.6.17.orig/include/linux/pm.h
+++ linux-2.6.17/include/linux/pm.h
@@ -24,6 +24,7 @@
 #ifdef __KERNEL__

 #include <linux/list.h>
+#include <linux/kobject.h>
 #include <asm/atomic.h>

 /*
@@ -108,7 +109,36 @@ typedef int __bitwise suspend_state_t;
 #define PM_SUSPEND_STANDBY     ((__force suspend_state_t) 1)
 #define PM_SUSPEND_MEM         ((__force suspend_state_t) 3)
 #define PM_SUSPEND_DISK                ((__force suspend_state_t) 4)
-#define PM_SUSPEND_MAX         ((__force suspend_state_t) 5)
+#define PM_FREQ_CHANGE         ((__force suspend_state_t) 5)
+#define PM_VOLT_CHANGE         ((__force suspend_state_t) 6)
+#define PM_SUSPEND_MAX         ((__force suspend_state_t) 7)
+
+struct oppoint {
+       struct list_head list;
+       suspend_state_t type;
+       unsigned int flags;
+       char *name;
+       unsigned int frequency;         /* in KHz */
+       unsigned int voltage;           /* mV */
+       unsigned int latency;           /* transition latency in us */
+       int     (*prepare_transition)(struct oppoint *cur, struct oppoint *new);
+       int     (*transition)(struct oppoint *cur, struct oppoint *new);
+       int     (*finish_transition)(struct oppoint *cur, struct oppoint *new);
+
+       void *md_data;                  /* arch dependent data */
+       struct kobject kobj;
+};
+
+
+extern struct oppoint pm_states;
+extern struct oppoint *current_state;
+extern unsigned long oppoint_compute_lpj(unsigned long ref, u_int
div, u_int mult);
+extern int register_operating_point(struct oppoint *opt);
+extern int unregister_operating_point(struct oppoint *opt);
+struct notifier_block;
+extern void oppoint_register_scale(struct notifier_block *nb, int level);
+extern void oppoint_unregister_scale(struct notifier_block *nb, int level);
+extern int oppoint_driver_scale(int level, struct oppoint *new);

 typedef int __bitwise suspend_disk_method_t;

@@ -128,7 +158,7 @@ struct pm_ops {

 extern void pm_set_ops(struct pm_ops *);
 extern struct pm_ops *pm_ops;
-extern int pm_suspend(suspend_state_t state);
+extern int pm_suspend(struct oppoint *state);


 /*
Index: linux-2.6.17/kernel/power/power.h
===================================================================
--- linux-2.6.17.orig/kernel/power/power.h
+++ linux-2.6.17/kernel/power/power.h
@@ -113,4 +113,4 @@ extern int swsusp_resume(void);
 extern int swsusp_read(void);
 extern int swsusp_write(void);
 extern void swsusp_close(void);
-extern int suspend_enter(suspend_state_t state);
+extern int suspend_enter(struct oppoint * state);
Index: linux-2.6.17/drivers/base/driver.c
===================================================================
--- linux-2.6.17.orig/drivers/base/driver.c
+++ linux-2.6.17/drivers/base/driver.c
@@ -12,6 +12,7 @@
 #include <linux/module.h>
 #include <linux/errno.h>
 #include <linux/string.h>
+#include <linux/pm.h>
 #include "base.h"

 #define to_dev(node) container_of(node, struct device, driver_list)
Index: linux-2.6.17/drivers/base/power/Makefile
===================================================================
--- linux-2.6.17.orig/drivers/base/power/Makefile
+++ linux-2.6.17/drivers/base/power/Makefile
@@ -1,4 +1,4 @@
-obj-y                  := shutdown.o
+obj-y                  := shutdown.o oppoint.o
 obj-$(CONFIG_PM)       += main.o suspend.o resume.o runtime.o sysfs.o
 obj-$(CONFIG_PM_TRACE) += trace.o

Index: linux-2.6.17/drivers/base/power/oppoint.c
===================================================================
--- /dev/null
+++ linux-2.6.17/drivers/base/power/oppoint.c
@@ -0,0 +1,74 @@
+/*
+ * oppoint.c -- OpPoint ower Management support (hotplug events and device
+ * scaling).
+ *
+ * (c) 2006 MontaVista Software, Inc. This file is licensed under the
+ * terms of the GNU General Public License version 2. This program is
+ * licensed "as is" without any warranty of any kind, whether express or
+ * implied.
+ */
+
+#include <linux/device.h>
+#include <linux/pm.h>
+#include <linux/sched.h>
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/notifier.h>
+
+#include "power.h"
+static RAW_NOTIFIER_HEAD(oppoint_scale_notifier);
+static DECLARE_MUTEX(oppoint_scale_sem);
+
+/* This function may be called by the platform frequency scaler before
+   or after a frequency change, in order to let drivers adjust any
+   clocks or calculations for the new frequency. */
+
+int oppoint_driver_scale(int level, struct oppoint *newop)
+{
+        if (down_trylock(&oppoint_scale_sem))
+                return 1;
+
+        raw_notifier_call_chain(&oppoint_scale_notifier, level, newop);
+        up(&oppoint_scale_sem);
+       return 0;
+}
+
+void oppoint_register_scale(struct notifier_block *nb, int level)
+{
+        down(&oppoint_scale_sem);
+        raw_notifier_chain_register(&oppoint_scale_notifier, nb);
+        up(&oppoint_scale_sem);
+}
+
+void oppoint_unregister_scale(struct notifier_block *nb, int level)
+{
+        down(&oppoint_scale_sem);
+        raw_notifier_chain_unregister(&oppoint_scale_notifier, nb);
+        up(&oppoint_scale_sem);
+}
+
+EXPORT_SYMBOL(oppoint_driver_scale);
+EXPORT_SYMBOL(oppoint_register_scale);
+EXPORT_SYMBOL(oppoint_unregister_scale);
+
+unsigned long oppoint_compute_lpj(unsigned long ref, u_int div, u_int mult)
+{
+       unsigned long new_jiffy_l, new_jiffy_h;
+
+       /*
+        * Recalculate loops_per_jiffy.  We do it this way to
+        * avoid math overflow on 32-bit machines.  Maybe we
+        * should make this architecture dependent?  If you have
+        * a better way of doing this, please replace!
+        *
+        *    new = old * mult / div
+        */
+        new_jiffy_h = ref / div;
+        new_jiffy_l = (ref % div) / 100;
+        new_jiffy_h *= mult;
+        new_jiffy_l = new_jiffy_l * mult / div;
+
+        return new_jiffy_h + new_jiffy_l * 100;
+}
+EXPORT_SYMBOL(oppoint_compute_lpj);


David
>
> thanks,
>
> greg k-h
>

Re: OpPoint summary

[David Singleton]

> Care to resend your patches in the proper format, through email so that
> we can see them, and possibly get some testing in -mm if they look sane?

Greg,
   here's the patch that leverages the cpufreq notifier lists for
driver PRE and POST
change functions.  I'm also rebasing to 2.6.18-rc7 and making changes Pavel
suggested about just having suspend states in /sys/power/state and moving
the operating point control file down under
/sys/power/operating_states directory.


Signed-Off-by: David Singleton <dsingleton@mvista.com>

 drivers/cpufreq/cpufreq.c |   36 ++++++++++++++++++++++++++++++++++++
 include/linux/cpufreq.h   |    2 ++
 2 files changed, 38 insertions(+)

Index: linux-2.6.17/drivers/cpufreq/cpufreq.c
===================================================================
--- linux-2.6.17.orig/drivers/cpufreq/cpufreq.c
+++ linux-2.6.17/drivers/cpufreq/cpufreq.c
@@ -226,6 +226,35 @@ static void adjust_jiffies(unsigned long
 static inline void adjust_jiffies(unsigned long val, struct
cpufreq_freqs *ci) { return; }
 #endif

+int cpufreq_prepare_transition(struct oppoint *cur, struct oppoint *new)
+{
+       struct cpufreq_freqs freqs;
+
+       freqs.old = cur->frequency;
+       freqs.new = new->frequency;
+       freqs.cpu = 0;
+       freqs.flags = new->flags;
+       blocking_notifier_call_chain(&cpufreq_transition_notifier_list,
+                       CPUFREQ_PRECHANGE, &freqs);
+       adjust_jiffies(CPUFREQ_PRECHANGE, &freqs);
+       return 0;
+}
+EXPORT_SYMBOL(cpufreq_prepare_transition);
+
+int cpufreq_finish_transition(struct oppoint *cur, struct oppoint *new)
+{
+       struct cpufreq_freqs freqs;
+
+       freqs.old = cur->frequency;
+       freqs.new = new->frequency;
+       freqs.cpu = 0;
+       freqs.flags = new->flags;
+       adjust_jiffies(CPUFREQ_POSTCHANGE, &freqs);
+       blocking_notifier_call_chain(&cpufreq_transition_notifier_list,
+                       CPUFREQ_POSTCHANGE, &freqs);
+       return 0;
+}
+EXPORT_SYMBOL(cpufreq_finish_transition);

 /**
  * cpufreq_notify_transition - call notifier chain and adjust_jiffies
@@ -920,6 +949,12 @@ static void cpufreq_out_of_sync(unsigned
 }


+#ifdef CONFIG_PM
+unsigned int cpufreq_quick_get(unsigned int cpu)
+{
+       return (current_state->frequency);
+}
+#else
 /**
  * cpufreq_quick_get - get the CPU frequency (in kHz) frpm policy->cur
  * @cpu: CPU number
@@ -941,6 +976,7 @@ unsigned int cpufreq_quick_get(unsigned

        return (ret);
 }
+#endif
 EXPORT_SYMBOL(cpufreq_quick_get);


Index: linux-2.6.17/include/linux/cpufreq.h
===================================================================
--- linux-2.6.17.orig/include/linux/cpufreq.h
+++ linux-2.6.17/include/linux/cpufreq.h
@@ -268,6 +268,8 @@ static inline unsigned int cpufreq_quick
        return 0;
 }
 #endif
+int cpufreq_prepare_transition(struct oppoint *cur, struct oppoint *new);
+int cpufreq_finish_transition(struct oppoint *cur, struct oppoint *new);


 /*********************************************************************



>
> thanks,
>
> greg k-h
>

Re: OpPoint summary

[David Singleton]

>
> Care to resend your patches in the proper format, through email so that
> we can see them, and possibly get some testing in -mm if they look sane?

Greg,
   here's the patch that implements operating points for different frequencies
for the speedstep-centrino line of processors.  Operating points are created
in much the same manner that cpufreq tables are.  This works for both
simple implementations like the centrino and more complex SoC systems
like the arm-pxa72x which has several clocks to control, and different clock
divisors and multipliers.

David


Signed-Off-by: David Singleton <dsingleton@mvista.com>

 arch/i386/Kconfig                                |    2
 arch/i386/kernel/cpu/Makefile                    |    1
 arch/i386/kernel/cpu/power/Kconfig               |  168 ++++++++++
 arch/i386/kernel/cpu/power/Makefile              |    2
 arch/i386/kernel/cpu/power/centrino-on-the-fly.c |   72 ++++
 arch/i386/kernel/cpu/power/centrino-speedstep.c  |  368 +++++++++++++++++++++++
 arch/i386/kernel/i386_ksyms.c                    |    4
 7 files changed, 617 insertions(+)

Index: linux-2.6.17/arch/i386/kernel/cpu/Makefile
===================================================================
--- linux-2.6.17.orig/arch/i386/kernel/cpu/Makefile
+++ linux-2.6.17/arch/i386/kernel/cpu/Makefile
@@ -17,3 +17,4 @@ obj-$(CONFIG_X86_MCE) +=      mcheck/

 obj-$(CONFIG_MTRR)     +=      mtrr/
 obj-$(CONFIG_CPU_FREQ) +=      cpufreq/
+obj-$(CONFIG_PM)       +=      power/
Index: linux-2.6.17/arch/i386/kernel/i386_ksyms.c
===================================================================
--- linux-2.6.17.orig/arch/i386/kernel/i386_ksyms.c
+++ linux-2.6.17/arch/i386/kernel/i386_ksyms.c
@@ -28,3 +28,7 @@ EXPORT_SYMBOL(__read_lock_failed);
 #endif

 EXPORT_SYMBOL(csum_partial);
+#ifdef CONFIG_PM
+#include <linux/pm.h>
+EXPORT_SYMBOL(pm_states);
+#endif
Index: linux-2.6.17/arch/i386/Kconfig
===================================================================
--- linux-2.6.17.orig/arch/i386/Kconfig
+++ linux-2.6.17/arch/i386/Kconfig
@@ -964,6 +964,8 @@ config APM_REAL_MODE_POWER_OFF

 endmenu

+source "arch/i386/kernel/cpu/power/Kconfig"
+
 source "arch/i386/kernel/cpu/cpufreq/Kconfig"

 endmenu
Index: linux-2.6.17/arch/i386/kernel/cpu/power/Makefile
===================================================================
--- /dev/null
+++ linux-2.6.17/arch/i386/kernel/cpu/power/Makefile
@@ -0,0 +1,2 @@
+obj-m                                  += centrino-on-the-fly.o
+obj-$(CONFIG_X86_SPEEDSTEP_CENTRINO)   += centrino-speedstep.o
Index: linux-2.6.17/arch/i386/kernel/cpu/power/centrino-speedstep.c
===================================================================
--- /dev/null
+++ linux-2.6.17/arch/i386/kernel/cpu/power/centrino-speedstep.c
@@ -0,0 +1,368 @@
+/*
+ * OpPoint support for Enhanced SpeedStep, as found in Intel's Pentium
+ * M (part of the Centrino chipset).
+ *
+ * Modelled on speedstep-centrino.c
+ *
+ * Author: David Singleton dsingleton@mvista.com MontaVista Software, Inc.
+ *
+ * 2006 (c) MontaVista Software, Inc. This file is licensed under
+ * the terms of the GNU General Public License version 2. This program
+ * is licensed "as is" without any warranty of any kind, whether express
+ * or implied.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/pm.h>
+#include <linux/delay.h>
+#include <linux/cpufreq.h>
+#include <linux/moduleparam.h>
+#include <linux/moduleloader.h>
+
+struct cpu_id
+{
+       __u8    x86;            /* CPU family */
+       __u8    x86_model;      /* model */
+       __u8    x86_mask;       /* stepping */
+};
+
+enum {
+       CPU_BANIAS,
+       CPU_DOTHAN_A1,
+       CPU_DOTHAN_A2,
+       CPU_DOTHAN_B0,
+       CPU_MP4HT_D0,
+       CPU_MP4HT_E0,
+};
+
+static const struct cpu_id cpu_ids[] = {
+       [CPU_BANIAS]    = { 6,  9, 5 },
+       [CPU_DOTHAN_A1] = { 6, 13, 1 },
+       [CPU_DOTHAN_A2] = { 6, 13, 2 },
+       [CPU_DOTHAN_B0] = { 6, 13, 6 },
+       [CPU_MP4HT_D0]  = {15,  3, 4 },
+       [CPU_MP4HT_E0]  = {15,  4, 1 },
+};
+#define N_IDS  ARRAY_SIZE(cpu_ids)
+
+struct cpu_model
+{
+       const struct cpu_id *cpu_id;
+       const char      *model_name;
+       unsigned        max_freq; /* max clock in kHz */
+
+};
+static int centrino_verify_cpu_id(const struct cpuinfo_x86 *c, const
struct cpu_id *x);
+
+void centrino_set_frequency(struct oppoint *op, uint freq, uint volt)
+{
+       op->frequency = freq * 1000;
+       op->voltage = volt;
+       op->md_data = (void *)(((freq / 100) << 8) | (volt - 700) / 16);
+}
+EXPORT_SYMBOL(centrino_set_frequency);
+
+int centrino_transition(struct oppoint *cur, struct oppoint *new)
+{
+       unsigned int msr, oldmsr = 0, h = 0;
+
+       if (cur == new)
+               return 0;
+
+       msr = (unsigned int)new->md_data;
+       rdmsr(MSR_IA32_PERF_CTL, oldmsr, h);
+
+       /* all but 16 LSB are reserved, treat them with care */
+       oldmsr &= ~0xffff;
+       msr &= 0xffff;
+       oldmsr |= msr;
+
+       wrmsr(MSR_IA32_PERF_CTL, oldmsr, h);
+
+       udelay(new->latency);
+
+       return 0;
+}
+EXPORT_SYMBOL(centrino_transition);
+
+#define _BANIAS(cpuid, max, name)      \
+{      .cpu_id         = cpuid,        \
+       .model_name     = "Intel(R) Pentium(R) M processor " name "MHz", \
+       .max_freq       = (max)*1000,   \
+}
+#define BANIAS(max)    _BANIAS(&cpu_ids[CPU_BANIAS], max, #max)
+
+/*
+ * CPU models, their operating frequency range, and freq/voltage
+ * operating points
+ */
+static struct cpu_model models[] =
+{
+       _BANIAS(&cpu_ids[CPU_BANIAS], 900, " 900"),
+       BANIAS(1000),
+       BANIAS(1100),
+       BANIAS(1200),
+       BANIAS(1300),
+       BANIAS(1400),
+       BANIAS(1500),
+       BANIAS(1600),
+       BANIAS(1700),
+
+       /* NULL model_name is a wildcard */
+       { &cpu_ids[CPU_DOTHAN_A1], NULL, 0},
+       { &cpu_ids[CPU_DOTHAN_A2], NULL, 0},
+       { &cpu_ids[CPU_DOTHAN_B0], NULL, 0},
+       { &cpu_ids[CPU_MP4HT_D0], NULL, 0},
+       { &cpu_ids[CPU_MP4HT_E0], NULL, 0},
+
+       { NULL, }
+};
+#undef _BANIAS
+#undef BANIAS
+
+static struct oppoint lowest = {
+       .name = "lowest",
+       .type = PM_FREQ_CHANGE,
+       .frequency = 0,
+       .voltage = 0,
+       .latency = 15,
+       .prepare_transition  = cpufreq_prepare_transition,
+       .transition = centrino_transition,
+       .finish_transition = cpufreq_finish_transition,
+};
+
+static struct oppoint low = {
+       .name = "low",
+       .type = PM_FREQ_CHANGE,
+       .latency = 15,
+       .prepare_transition  = cpufreq_prepare_transition,
+       .transition = centrino_transition,
+       .finish_transition = cpufreq_finish_transition,
+};
+
+static struct oppoint mediumlow = {
+       .name = "mediumlow",
+       .type = PM_FREQ_CHANGE,
+       .latency = 15,
+       .prepare_transition  = cpufreq_prepare_transition,
+       .transition = centrino_transition,
+       .finish_transition = cpufreq_finish_transition,
+};
+
+static struct oppoint medium = {
+       .name = "medium",
+       .type = PM_FREQ_CHANGE,
+       .latency = 15,
+       .prepare_transition  = cpufreq_prepare_transition,
+       .transition = centrino_transition,
+       .finish_transition = cpufreq_finish_transition,
+};
+
+static struct oppoint mediumhigh = {
+       .name = "mediumhigh",
+       .type = PM_FREQ_CHANGE,
+       .latency = 15,
+       .prepare_transition  = cpufreq_prepare_transition,
+       .transition = centrino_transition,
+       .finish_transition = cpufreq_finish_transition,
+};
+
+static struct oppoint high = {
+       .name = "high",
+       .type = PM_FREQ_CHANGE,
+       .latency = 15,
+       .prepare_transition  = cpufreq_prepare_transition,
+       .transition = centrino_transition,
+       .finish_transition = cpufreq_finish_transition,
+};
+
+static struct oppoint highest = {
+       .name = "highest",
+       .type = PM_FREQ_CHANGE,
+       .latency = 15,
+       .prepare_transition  = cpufreq_prepare_transition,
+       .transition = centrino_transition,
+       .finish_transition = cpufreq_finish_transition,
+};
+
+static int __init centrino_init_oppoint(void)
+{
+       struct cpuinfo_x86 *cpu = &cpu_data[0];
+       struct cpu_model *model;
+
+       for(model = models; model->cpu_id != NULL; model++) {
+               if (centrino_verify_cpu_id(cpu, model->cpu_id) &&
+                   (model->model_name == NULL ||
+                    strcmp(cpu->x86_model_id, model->model_name) == 0))
+                       break;
+       }
+
+       if (model->cpu_id == NULL) {
+               /* No match at all */
+               printk("OpPoint: no support for CPU model %s\n",
+                   cpu->x86_model_id);
+               return -ENOENT;
+       }
+
+       switch (model->max_freq) {
+       /* Ultra Low Voltage Intel Pentium M processor 900MHz (Banias) */
+           case (900000) :
+           {
+               centrino_set_frequency(&low, 600, 844);
+               centrino_set_frequency(&medium, 800, 988);
+               centrino_set_frequency(&high, 900, 1004);
+               break;
+           }
+       /* Ultra Low Voltage Intel Pentium M processor 1.00GHz (Banias) */
+           case (1000000) :
+           {
+               centrino_set_frequency(&low, 600, 844);
+               centrino_set_frequency(&medium, 800, 972);
+               centrino_set_frequency(&high, 900, 988);
+               centrino_set_frequency(&highest, 1000, 1004);
+               break;
+           }
+       /* Ultra Low Voltage Intel Pentium M processor 1.10GHz (Banias) */
+           case (1100000) :
+           {
+               centrino_set_frequency(&lowest, 600, 956);
+               centrino_set_frequency(&low, 800, 1020);
+               centrino_set_frequency(&medium, 900, 1100);
+               centrino_set_frequency(&high, 1000, 1164);
+               centrino_set_frequency(&highest, 1100, 1180);
+               break;
+           }
+       /* Ultra Low Voltage Intel Pentium M processor 1.10GHz (Banias) */
+           case (1200000) :
+           {
+               centrino_set_frequency(&lowest, 600, 956);
+               centrino_set_frequency(&low, 800, 1004);
+               centrino_set_frequency(&medium, 900, 1020);
+               centrino_set_frequency(&mediumhigh, 1000, 1100);
+               centrino_set_frequency(&high, 1100, 1164);
+               centrino_set_frequency(&highest, 1200, 1180);
+               break;
+           }
+       /* Ultra Low Voltage Intel Pentium M processor 1.10GHz (Banias) */
+           case (1300000) :
+           {
+               centrino_set_frequency(&lowest, 600, 956);
+               centrino_set_frequency(&low, 800, 1260);
+               centrino_set_frequency(&medium, 1000, 1292);
+               centrino_set_frequency(&high, 1200, 1356);
+               centrino_set_frequency(&highest, 1300, 1388);
+               break;
+           }
+       /* Ultra Low Voltage Intel Pentium M processor 1.10GHz (Banias) */
+           case (1400000) :
+           {
+               centrino_set_frequency(&lowest, 600, 956);
+               centrino_set_frequency(&low, 800, 1180);
+               centrino_set_frequency(&medium, 1000, 1308);
+               centrino_set_frequency(&high, 1200, 1436);
+               centrino_set_frequency(&highest, 1400, 1484);
+               break;
+           }
+       /* Ultra Low Voltage Intel Pentium M processor 1.10GHz (Banias) */
+           case (1500000) :
+           {
+               centrino_set_frequency(&lowest, 600, 956);
+               centrino_set_frequency(&low, 800, 1116);
+               centrino_set_frequency(&medium, 1000, 1228);
+               centrino_set_frequency(&mediumhigh, 1200, 1356);
+               centrino_set_frequency(&high, 1400, 1452);
+               centrino_set_frequency(&highest, 1500, 1484);
+               break;
+           }
+       /* Ultra Low Voltage Intel Pentium M processor 1.10GHz (Banias) */
+           case (1600000) :
+           {
+               centrino_set_frequency(&lowest, 600, 956);
+               centrino_set_frequency(&low, 800, 1036);
+               centrino_set_frequency(&medium, 1000, 1164);
+               centrino_set_frequency(&mediumhigh, 1200, 1276);
+               centrino_set_frequency(&high, 1400, 1420);
+               centrino_set_frequency(&highest, 1600, 1484);
+               break;
+           }
+       /* Ultra Low Voltage Intel Pentium M processor 1.10GHz (Banias) */
+           case (1700000) :
+           {
+               centrino_set_frequency(&lowest, 600, 956);
+               centrino_set_frequency(&low, 800, 1004);
+               centrino_set_frequency(&medium, 1000, 1116);
+               centrino_set_frequency(&mediumhigh, 1200, 1228);
+               centrino_set_frequency(&high, 1400, 1308);
+               centrino_set_frequency(&highest, 1700, 1484);
+               break;
+           }
+       }
+       if (lowest.frequency) {
+               register_operating_point(&lowest);
+               list_add_tail(&lowest.list, &pm_states.list);
+       }
+       if (low.frequency) {
+               register_operating_point(&low);
+               list_add_tail(&low.list, &pm_states.list);
+       }
+       if (mediumlow.frequency) {
+               register_operating_point(&mediumlow);
+               list_add_tail(&mediumlow.list, &pm_states.list);
+       }
+       if (medium.frequency) {
+               register_operating_point(&medium);
+               list_add_tail(&medium.list, &pm_states.list);
+       }
+       if (mediumhigh.frequency) {
+               register_operating_point(&mediumhigh);
+               list_add_tail(&mediumhigh.list, &pm_states.list);
+       }
+       if (high.frequency) {
+               register_operating_point(&high);
+               list_add_tail(&high.list, &pm_states.list);
+               current_state = &high;
+       }
+       if (highest.frequency) {
+               register_operating_point(&highest);
+               list_add_tail(&highest.list, &pm_states.list);
+               current_state = &highest;
+       }
+       return 0;
+}
+
+static void centrino_exit_oppoint(void)
+{
+       if (lowest.frequency)
+               list_del_init(&lowest.list);
+       if (low.frequency)
+               list_del_init(&low.list);
+       if (mediumlow.frequency)
+               list_del_init(&mediumlow.list);
+       if (medium.frequency)
+               list_del_init(&medium.list);
+       if (mediumhigh.frequency)
+               list_del_init(&mediumhigh.list);
+       if (high.frequency)
+               list_del_init(&high.list);
+       if (highest.frequency)
+               list_del_init(&highest.list);
+       return;
+}
+
+static int centrino_verify_cpu_id(const struct cpuinfo_x86 *c, const
struct cpu_id *x)
+{
+       if ((c->x86 == x->x86) &&
+           (c->x86_model == x->x86_model) &&
+           (c->x86_mask == x->x86_mask))
+               return 1;
+       return 0;
+}
+
+MODULE_AUTHOR ("David Singleton <dsingleton@mvista.com>");
+MODULE_DESCRIPTION ("OpPoint operting points for Intel Pentium M processors.");
+MODULE_LICENSE ("GPL");
+
+late_initcall(centrino_init_oppoint);
+module_exit(centrino_exit_oppoint);
Index: linux-2.6.17/arch/i386/kernel/cpu/power/Kconfig
===================================================================
--- /dev/null
+++ linux-2.6.17/arch/i386/kernel/cpu/power/Kconfig
@@ -0,0 +1,168 @@
+#
+# Operating Point support for frequency/voltage scaling
+#
+
+menu "CPU Frequency/Voltage scaling"
+
+if CPU_PM
+
+comment "OpPoint processor support"
+
+config ELAN_OPPOINT
+       tristate "AMD Elan SC400 and SC410"
+       depends on X86_ELAN
+       ---help---
+         This adds the OpPoint support for AMD Elan SC400 and SC410
+         processors.
+
+         You need to specify the processor maximum speed as boot
+         parameter: elanfreq=maxspeed (in kHz) or as module
+         parameter "max_freq".
+
+         If in doubt, say N.
+
+config SC520_OPPOINT
+       tristate "AMD Elan SC520"
+       depends on X86_ELAN
+       ---help---
+         This adds OpPoint support for AMD Elan SC520 processor.
+
+         If in doubt, say N.
+
+
+config X86_POWERNOW_K6
+       tristate "AMD Mobile K6-2/K6-3 PowerNow!"
+       help
+         This adds OpPoint support for mobile AMD K6-2+ and mobile
+         AMD K6-3+ processors.
+
+         If in doubt, say N.
+
+config X86_POWERNOW_K7
+       tristate "AMD Mobile Athlon/Duron PowerNow!"
+       help
+         This adds OpPoint support for mobile AMD K7 mobile processors.
+
+         If in doubt, say N.
+
+config X86_POWERNOW_K7_ACPI
+       bool
+       depends on X86_POWERNOW_K7 && ACPI_PROCESSOR
+       depends on !(X86_POWERNOW_K7 = y && ACPI_PROCESSOR = m)
+       default y
+
+config X86_POWERNOW_K8
+       tristate "AMD Opteron/Athlon64 PowerNow!"
+       depends on EXPERIMENTAL
+       help
+         This adds OpPoint support for mobile AMD Opteron/Athlon64 processors.
+
+         If in doubt, say N.
+
+config X86_POWERNOW_K8_ACPI
+       bool
+       depends on X86_POWERNOW_K8 && ACPI_PROCESSOR
+       depends on !(X86_POWERNOW_K8 = y && ACPI_PROCESSOR = m)
+       default y
+
+config X86_GX_SUSPMOD
+       tristate "Cyrix MediaGX/NatSemi Geode Suspend Modulation"
+       depends on PCI
+       help
+        This add OpPoint support for NatSemi Geode processors which
+        support suspend modulation.
+
+        If in doubt, say N.
+
+config X86_SPEEDSTEP_CENTRINO
+       tristate "Intel Enhanced SpeedStep"
+       select X86_SPEEDSTEP_CENTRINO_TABLE if (!X86_SPEEDSTEP_CENTRINO_ACPI)
+       help
+         This adds OpPoint support for Enhanced SpeedStep enabled
+         mobile CPUs.  This means Intel Pentium M (Centrino) CPUs. However,
+         you also need to say Y to "Use ACPI tables to decode..." below
+         [which might imply enabling ACPI] if you want to use this driver
+         on non-Banias CPUs.
+
+         If in doubt, say N.
+
+config X86_SPEEDSTEP_CENTRINO_ACPI
+       bool "Use ACPI tables to decode valid frequency/voltage pairs"
+       depends on X86_SPEEDSTEP_CENTRINO && ACPI_PROCESSOR
+       depends on !(X86_SPEEDSTEP_CENTRINO = y && ACPI_PROCESSOR = m)
+       default y
+       help
+         Use primarily the information provided in the BIOS ACPI tables
+         to determine valid CPU frequency and voltage pairings. It is
+         required for the driver to work on non-Banias CPUs.
+
+         If in doubt, say Y.
+
+config X86_SPEEDSTEP_CENTRINO_TABLE
+       bool "Built-in tables for Banias CPUs"
+       depends on X86_SPEEDSTEP_CENTRINO
+       default y
+       help
+         Use built-in tables for Banias CPUs if ACPI encoding
+         is not available.
+
+         If in doubt, say N.
+
+config X86_SPEEDSTEP_ICH
+       tristate "Intel Speedstep on ICH-M chipsets (ioport interface)"
+       help
+         This adds the OpPoint support for certain mobile Intel Pentium III
+         (Coppermine), all mobile Intel Pentium III-M (Tualatin) and all
+         mobile Intel Pentium 4 P4-M on systems which have an Intel ICH2,
+         ICH3 or ICH4 southbridge.
+
+         If in doubt, say N.
+
+config X86_SPEEDSTEP_SMI
+       tristate "Intel SpeedStep on 440BX/ZX/MX chipsets (SMI interface)"
+       depends on EXPERIMENTAL
+       help
+         This adds OpPoint support for certain mobile Intel Pentium III
+         (Coppermine), all mobile Intel Pentium III-M (Tualatin)
+         on systems which have an Intel 440BX/ZX/MX southbridge.
+
+         If in doubt, say N.
+
+config X86_P4_CLOCKMOD
+       tristate "Intel Pentium 4 clock modulation"
+       help
+         This adds OpPoint support for Intel Pentium 4 / XEON
+         processors.
+
+         If in doubt, say N.
+
+config X86_OPPOINT_NFORCE2
+       tristate "nVidia nForce2 FSB changing"
+       depends on EXPERIMENTAL
+       help
+         This adds OpPoint support for FSB changing on nVidia nForce2
+         platforms.
+
+         If in doubt, say N.
+
+config X86_LONGRUN
+       tristate "Transmeta LongRun"
+       help
+         This adds OpPoint support for Transmeta Crusoe and Efficeon processors
+         which support LongRun.
+
+         If in doubt, say N.
+
+config X86_LONGHAUL
+       tristate "VIA Cyrix III Longhaul"
+       depends on ACPI_PROCESSOR
+       help
+         This adds OpPoint support for VIA Samuel/CyrixIII,
+         VIA Cyrix Samuel/C3, VIA Cyrix Ezra and VIA Cyrix Ezra-T
+         processors.
+
+         If in doubt, say N.
+
+endif  #  CONFIG_PM
+
+endmenu
Index: linux-2.6.17/arch/i386/kernel/cpu/power/centrino-on-the-fly.c
===================================================================
--- /dev/null
+++ linux-2.6.17/arch/i386/kernel/cpu/power/centrino-on-the-fly.c
@@ -0,0 +1,72 @@
+/*
+ * power/centrino-on-the-fly.c
+ *
+ * This is the template to create a dynamic operating point.
+ *
+ * Author: David Singleton dsingleton@mvista.com MontaVista Software, Inc.
+ *
+ * 2006 (c) MontaVista Software, Inc. This file is licensed under
+ * the terms of the GNU General Public License version 2. This program
+ * is licensed "as is" without any warranty of any kind, whether express
+ * or implied.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/pm.h>
+#include <linux/cpufreq.h>
+#include <linux/moduleparam.h>
+#include <linux/moduleloader.h>
+
+int centrino_transition(struct oppoint *cur, struct oppoint *new);
+
+static unsigned int frequency = 1000;
+static unsigned int voltage = 1308;
+static unsigned int latency = 100;
+module_param_named(frequency, frequency, uint, 0);
+module_param_named(voltage, voltage, uint, 0);
+module_param_named(latency, latency, uint, 0);
+MODULE_PARM_DESC(frequency, "cpu frequency in kHz");
+MODULE_PARM_DESC(voltage, "cpu voltage in mV");
+MODULE_PARM_DESC(latency, "transition latency in us");
+
+/* Register both the driver and the device */
+
+static struct oppoint dynamic_op = {
+       .type = PM_FREQ_CHANGE,
+       .name = "dynamic",
+       .prepare_transition = cpufreq_prepare_transition,
+       .transition = centrino_transition,
+       .finish_transition = cpufreq_finish_transition,
+};
+
+extern void centrino_set_frequency(struct oppoint *op, uint freq, uint volt);
+
+int __init dynamic_oppoint_init(void)
+{
+
+       printk("Dynamic OpPoint operating point for speedstep centrino\n");
+       dynamic_op.frequency = frequency;
+       dynamic_op.voltage = voltage;
+       dynamic_op.latency = latency;
+       centrino_set_frequency(&dynamic_op, frequency / 1000, voltage);
+       register_operating_point(&dynamic_op);
+       printk("OpPoint: freq %d volt %d msr 0x%x\n", dynamic_op.frequency,
+          dynamic_op.voltage, (unsigned int)dynamic_op.md_data);
+       list_add_tail(&dynamic_op.list, &pm_states.list);
+       return 0;
+}
+
+void __exit dynamic_oppoint_cleanup(void)
+{
+       unregister_operating_point(&dynamic_op);
+       list_del_init(&dynamic_op.list);
+}
+
+module_init(dynamic_oppoint_init);
+module_exit(dynamic_oppoint_cleanup);
+
+MODULE_AUTHOR("David Singleton <dsingleton@mvista.com>");
+MODULE_DESCRIPTION("Dynamic OpPoint for Intel Pentium M processor module");
+MODULE_LICENSE("GPL");

>
> thanks,
>
> greg k-h
>

Re: OpPoint summary

[David Singleton]

>
> Care to resend your patches in the proper format, through email so that
> we can see them, and possibly get some testing in -mm if they look sane?
>
> thanks,
>
> greg k-h
>

Greg,
   here's the arm-pxa7x patch which creates operating points for the much more
complex ARM platform.  It illustrates the straight forward nature of creating
operating points, both frequency and sleep states, for different and more
complex architectures, and eliminates the need to have users pass in all
the parameters needed to create an operating point.


Signed-Off-by: David Singleton <dsingleton@mvista.com>

 arch/arm/Kconfig                      |    2
 arch/arm/mach-pxa/Makefile            |    3
 arch/arm/mach-pxa/mainstone_freq.c    |  211 +++
 arch/arm/mach-pxa/mainstone_oppoint.c | 1910 ++++++++++++++++++++++++++++++++++
 arch/arm/mach-pxa/mainstone_volt.c    |  363 ++++++
 include/asm-arm/arch-pxa/oppoint.h    |  119 ++
 include/asm-arm/arch-pxa/pxa-regs.h   |    8
 7 files changed, 2614 insertions(+), 2 deletions(-)

Index: linux-2.6.17/arch/arm/mach-pxa/Makefile
===================================================================
--- linux-2.6.17.orig/arch/arm/mach-pxa/Makefile
+++ linux-2.6.17/arch/arm/mach-pxa/Makefile
@@ -10,7 +10,8 @@ obj-$(CONFIG_PXA27x) += pxa27x.o
 # Specific board support
 obj-$(CONFIG_ARCH_LUBBOCK) += lubbock.o
 obj-$(CONFIG_MACH_LOGICPD_PXA270) += lpd270.o
-obj-$(CONFIG_MACH_MAINSTONE) += mainstone.o
+obj-$(CONFIG_MACH_MAINSTONE) += mainstone.o mainstone_oppoint.o \
+mainstone_freq.o  mainstone_volt.o
 obj-$(CONFIG_ARCH_PXA_IDP) += idp.o
 obj-$(CONFIG_MACH_TRIZEPS4)    += trizeps4.o
 obj-$(CONFIG_PXA_SHARP_C7xx)   += corgi.o corgi_ssp.o corgi_lcd.o
sharpsl_pm.o corgi_pm.o
Index: linux-2.6.17/arch/arm/mach-pxa/mainstone_freq.c
===================================================================
--- /dev/null
+++ linux-2.6.17/arch/arm/mach-pxa/mainstone_freq.c
@@ -0,0 +1,211 @@
+/*
+ * linux/arch/arm/mach-pxa/mainstone_freq.c
+ *
+ * Functions to change CPU frequencies on the Bulverde processor
+ * adopted from Intel code for MontaVista Linux.
+ *
+ * Author: David Singleton <dsingleton@mvista.com>
+ *
+ * 2006 (c) MontaVista Software, Inc. This file is licensed under the
+ * terms of the GNU General Public License version 2. This program is
+ * licensed "as is" without any warranty of any kind, whether express
+ * or implied.
+ *
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/hardirq.h>
+#include <asm/io.h>
+
+#include <asm/hardware.h>
+#include <asm/arch/oppoint.h>
+#include <asm/arch/pxa-regs.h>
+#include <asm/pgtable.h>
+#include <asm/pgalloc.h>
+
+#include <asm/arch/mainstone.h>
+
+/*
+ * Since CPDIS and PPDIS is always the same, we use only one definition here.
+ */
+#define        PDIS    0       /* Core PLL and Peripheral PLL is
enabled after FCS. */
+
+/*
+ *     Available CPU frequency list for Bulverde.
+ */
+static unsigned int cpufreq_matrix[N_NUM][L_NUM + 1];
+static void mainstone_freq_debug_info(void);
+static volatile int *ramstart;
+
+/*
+ *  Init according to mainstone manual.
+ */
+static void mainstone_initialize_freq_matrix(void)
+{
+       int n, l;
+
+       memset(&cpufreq_matrix, 0, sizeof(cpufreq_matrix));
+
+       for (n = 2; n < N_NUM + 2; n++) {
+               for (l = 2; l <= L_NUM; l++) {
+                       cpufreq_matrix[n - 2][l - 2] = (13 * n * l / 2) * 1000;
+                       if (cpufreq_matrix[n - 2][l - 2] > BLVD_MAX_FREQ)
+                               cpufreq_matrix[n - 2][l - 2] = 0;
+               }
+       }
+}
+
+/*
+ * This should be called with a valid freq point that was
+ * obtained via mainstone_validate_speed
+ */
+void mainstone_set_freq(unsigned int CLKCFGValue)
+{
+       unsigned long flags;
+       unsigned int unused;
+       volatile int v;
+
+       local_irq_save(flags);
+
+       /*
+        * force a tlb fault to get the mapping into the tlb
+        * (otherwise this will occur below when the sdram is turned off and
+        * something-bad(tm) will happen)
+        */
+       v = *(volatile unsigned long *)ramstart;
+       *(volatile unsigned long *)ramstart = v;
+
+       MST_LEDDAT1 = CLKCFGValue;
+
+       __asm__ __volatile__(" \n\
+               ldr     r4, [%1]                        @load MDREFR \n\
+               mcr     p14, 0, %2, c6, c0, 0           @ set CCLKCFG[FCS] \n\
+               ldr     r5, =0xe3dfefff \n\
+               and     r4, r4, r5      \n\
+               str     r4,  [%1]                       @restore \n\
+               ":"=&r"(unused)
+                            :"r"(&MDREFR), "r"(CLKCFGValue), "r"(ramstart)
+                            :"r4", "r5");
+
+       MST_LEDDAT1 = 0x0002;
+       /*
+          NOTE: if we don't turn off IRQs up top, there is no point
+          to restoring them here.
+        */
+       local_irq_restore(flags);
+
+       /* spit out some info about what happened */
+       mainstone_freq_debug_info();
+
+}
+
+extern void mainstone_get_current_info(struct md_opt *);
+
+static void mainstone_freq_debug_info(void)
+{
+       unsigned int sysbus, run, t, turbo, mem, m = 1;
+       struct md_opt opt;
+
+       mainstone_get_current_info(&opt);
+
+       run = 13000 * opt.l;
+       turbo = (13000 * opt.l * opt.n) >> 1;
+       sysbus = (opt.b) ? run : (run / 2);
+       t = opt.regs.clkcfg & 0x1;
+
+       /* If CCCR[A] is on */
+       if (opt.cccra) {
+               mem = sysbus;
+       } else {
+               /* If A=0
+                  m initialized to 1 (for l=2-10)
+                */
+               if (opt.l > 10)
+                       m = 2;  /* for l=11-20 */
+               if (opt.l > 20)
+                       m = 4;  /* for l=21-31 */
+               mem = run / m;
+       }
+}
+
+int mainstone_get_freq(void)
+{
+       unsigned int freq, n, l, ccsr;
+
+       ccsr = CCSR;
+
+       l = ccsr & CCCR_L_MASK; /* Get L */
+       n = (ccsr & CCCR_N_MASK) >> 7;  /* Get 2N */
+
+       if (n < 2)
+               n = 2;
+
+       /* Shift to divide by 2 because N is really 2N */
+       freq = (13000 * l * n) >> 1;    /*      in kHz */
+
+       return freq;
+}
+
+unsigned int mainstone_read_clkcfg(void)
+{
+       unsigned int value = 0;
+       unsigned int un_used;
+
+        __asm__ __volatile__("mrc      p14, 0, %0, c6, c0, 0":
"=r"(value) : "r"(un_used) );
+
+       return value;
+}
+
+static int mainstone_init_freqs(void)
+{
+       int cpu_ver;
+
+       asm volatile ("mrc%? p15, 0, %0, c0, c0":"=r" (cpu_ver));
+
+       /*
+          Bulverde     A0:     0x69054110,
+          A1 :         0x69054111
+        */
+       if ((cpu_ver & 0x0000f000) >> 12 == 4 &&
+           (cpu_ver & 0xffff0000) >> 16 == 0x6905) {
+               /*    It is an xscale core bulverde chip. */
+               return 1;
+       }
+
+       return 0;
+}
+
+int mainstone_clk_init(void)
+{
+       unsigned int freq;
+
+       /*
+        * In order to turn the sdram back on (see below) we need to
+        * r/w the sdram.  We need to do this without the cache and
+        * write buffer in the way.  So, we temporarily ioremap the
+        * first page of sdram as uncached i/o memory and use the
+        * aliased address
+        */
+
+       /* map the first page of sdram to an uncached virtual page */
+       ramstart = (int *)ioremap(PHYS_OFFSET, 4096);
+
+       freq = mainstone_get_freq();    /*      in kHz */
+       printk(KERN_INFO "Init freq: %dkHz.\n", freq);
+
+       mainstone_initialize_freq_matrix();
+
+       if (mainstone_init_freqs()) {
+               printk(KERN_INFO "CPU frequency change initialized.\n");
+       }
+       return 0;
+}
+
+void mainstone_freq_cleanup(void)
+{
+       /* unmap the page we used*/
+       iounmap((void *)ramstart);
+}
Index: linux-2.6.17/arch/arm/mach-pxa/mainstone_volt.c
===================================================================
--- /dev/null
+++ linux-2.6.17/arch/arm/mach-pxa/mainstone_volt.c
@@ -0,0 +1,363 @@
+/*
+ * linux/arch/arm/mach-pxa/mainstone_volt.c
+ *
+ * Bulverde voltage change driver.
+ *
+ * Author: David Singleton dsingleton@mvista.com MontaVista Software, Inc.
+ *
+ * 2006 (c) MontaVista Software, Inc. This file is licensed under
+ * the terms of the GNU General Public License version 2. This program
+ * is licensed "as is" without any warranty of any kind, whether express
+ * or implied.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/init.h>
+#include <asm/hardware.h>
+#include <asm/arch/oppoint.h>
+#include <asm/arch/pxa-regs.h>
+
+/* For ioremap */
+#include <asm/io.h>
+
+#define CP15R0_REV_MASK                0x0000000f
+#define PXA270_C5              0x7
+
+static u32 chiprev;
+static unsigned int blvd_min_vol, blvd_max_vol;
+static int mvdt_size;
+
+static volatile int *ramstart;
+
+struct MvDAC {
+       unsigned int mv;
+       unsigned int DACIn;
+} *mvDACtable;
+
+/*
+ *  Transfer desired mv to required DAC value.
+ *  Vcore = 1.3v - ( 712uv * DACIn )
+ */
+static struct MvDAC table_c0[] = {
+       {1425, 0},
+       {1400, 69},
+       {1300, 248},
+       {1200, 428},
+       {1100, 601},
+       {1000, 777},
+       {950, 872},
+       {868, 1010},
+       {861, 0xFFFFFFFF},
+};
+
+/*
+ *  Transfer desired mv to required DAC value, update for new boards,
+ *  according to "Intel PXA27x Processor Developer's Kit User's Guide,
+ *  April 2004, Revision 4.001"
+ *  Vcore = 1.5V - (587uV * DAC(input)).
+ */
+static struct MvDAC table_c5[] = {
+       {1500, 0},
+       {1484,25},
+       {1471,50},
+       {1456,75},
+       {1441,100},
+       {1427,125},
+       {1412,150},
+       {1397,175},
+       {1383,200},
+       {1368,225},
+       {1353,250},
+       {1339,275},
+       {1323,300},
+       {1309,325},
+       {1294,350},
+       {1280,375},
+       {1265,400},
+       {1251,425},
+       {1236,450},
+       {1221,475},
+       {1207,500},
+       {1192,525},
+       {1177,550},
+       {1162,575},
+       {1148,600},
+       {1133,625},
+       {1118,650},
+       {1104,675},
+       {1089,700},
+       {1074,725},
+       {1060,750},
+       {1045,775},
+       {1030,800},
+       {1016,825},
+       {1001,850},
+       {986,875},
+       {972,900},
+       {957,925},
+       {942,950},
+       {928,975},
+       {913,1000},
+       {899, 1023},
+};
+
+unsigned int mainstone_validate_voltage(unsigned int mv)
+{
+       /*
+        *      Just to check whether user specified mv
+        *      can be set to the CPU.
+        */
+       if ((mv >= blvd_min_vol) && (mv <= blvd_max_vol)) {
+               return mv;
+       } else {
+               return 0;
+       }
+}
+
+/*
+ * Prepare for a voltage change, possibly coupled with a frequency
+ * change
+ */
+static void power_change_cmd(unsigned int DACValue, int coupled);
+void mainstone_prep_set_voltage(unsigned int mv)
+{
+        power_change_cmd(mv2DAC(mv), 1 /* coupled */ );
+}
+
+
+unsigned int mv2DAC(unsigned int mv)
+{
+       int i, num = mvdt_size;
+
+       if (mvDACtable[0].mv <= mv) {   /* Max or bigger */
+               /* Return the first one */
+               return mvDACtable[0].DACIn;
+       }
+
+       if (mvDACtable[num - 1].mv >= mv) {     /* Min or smaller */
+               /* Return the last one */
+               return mvDACtable[num - 1].DACIn;
+       }
+
+       /*
+        * The biggest and smallest value cases are covered, now the
+        *  loop may skip those
+        */
+       for (i = 1; i <= (num - 1); i++) {
+               if ((mvDACtable[i].mv >= mv) && (mvDACtable[i + 1].mv < mv)) {
+                       return mvDACtable[i].DACIn;
+               }
+       }
+
+       /* Should never get here */
+       return 0;
+}
+extern void mainstone_change_voltage(void);
+void vm_setvoltage(unsigned int DACValue)
+{
+       power_change_cmd(DACValue, 0 /* not-coupled */ );
+       /* Execute voltage change sequence      */
+       mainstone_change_voltage();     /* set VC on the PWRMODE on CP14 */
+}
+/*
+ *     According to bulverde's manual, set the core's voltage.
+ */
+void mainstone_set_voltage(unsigned int mv)
+{
+       vm_setvoltage(mv2DAC(mv));
+}
+
+/*
+ *     Functionality: Initialize PWR I2C.
+ *     Argument:      None
+ *     Return:        void
+*/
+int mainstone_vcs_init(void)
+{
+       /*
+        * we distinguish new and old boards by proc chip
+        * revision, we assume new boards have C5 proc
+        * revision and we use the new table (table_c5) for them,
+        * for all other boards we use the old table (table_c0).
+        * Note, the logics won't work and inaccurate voltage
+        * will be set if C5 proc installed to old board
+        * and vice versa.
+        */
+
+       asm("mrc%? p15, 0, %0, c0, c0" : "=r" (chiprev));
+
+       chiprev &= CP15R0_REV_MASK;
+
+       if ( chiprev == PXA270_C5 ) {
+               mvDACtable = table_c5;
+               mvdt_size = sizeof(table_c5) / sizeof(struct MvDAC);
+               blvd_min_vol = BLVD_MIN_VOL_C5;
+               blvd_max_vol = BLVD_MAX_VOL_C5;
+       } else {
+               mvDACtable = table_c0;
+               mvdt_size = sizeof(table_c0) / sizeof(struct MvDAC);
+               blvd_min_vol = BLVD_MIN_VOL_C0;
+               blvd_max_vol = BLVD_MAX_VOL_C0;
+       }
+
+       CKEN |= 0x1 << 15;
+       CKEN |= 0x1 << 14;
+       PCFR |= 0x60;
+
+       /* map the first page of sdram to an uncached virtual page */
+       ramstart = (int *)ioremap(PHYS_OFFSET, 4096);
+
+       printk(KERN_INFO "CPU voltage change initialized.\n");
+
+       return 0;
+}
+
+void mainstone_voltage_cleanup(void)
+{
+       /* unmap the page we used*/
+       iounmap((void *)ramstart);
+}
+
+
+void mainstone_change_voltage(void)
+{
+       unsigned long flags;
+       unsigned int unused;
+
+
+       local_irq_save(flags);
+
+       __asm__ __volatile__("\n\
+    @ BV B0 WORKAROUND - Core hangs on voltage change at different\n\
+    @ alignments and at different core clock frequencies\n\
+    @ To ensure that no external fetches occur, we want to store the next\n\
+    @ several instructions that occur after the voltage change inside\n\
+    @ the cache. The load dependency stall near the retry label ensures \n\
+    @ that any outstanding instruction cacheline loads are complete before \n\
+    @ the mcr instruction is executed on the 2nd pass. This procedure \n\
+    @ ensures us that the internal bus will not be busy. \n\
+                                       \n\
+    b      2f                          \n\
+    nop                                        \n\
+    .align  5                          \n\
+2:                                     \n\
+    ldr     r0, [%1]                   @ APB register read and compare \n\
+    cmp     r0, #0                     @ fence for pending slow apb reads \n\
+                                       \n\
+    mov     r0, #8                     @ VC bit for PWRMODE \n\
+    movs    r1, #1                     @ don't execute mcr on 1st pass \n\
+                                       \n\
+    @ %1 points to uncacheable memory to force memory read \n\
+                                       \n\
+retry:                                 \n\
+    ldreq   r3, [%2]                   @ only stall on the 2nd pass\n\
+    cmpeq   r3, #0                     @ cmp causes fence on mem transfers\n\
+    cmp     r1, #0                     @ is this the 2nd pass? \n\
+    mcreq   p14, 0, r0, c7, c0, 0      @ write to PWRMODE on 2nd pass only \n\
+                                       \n\
+    @ Read VC bit until it is 0, indicates that the VoltageChange is done.\n\
+    @ On first pass, we never set the VC bit, so it will be clear already.\n\
+                                       \n\
+VoltageChange_loop:                    \n\
+    mrc     p14, 0, r3, c7, c0, 0      \n\
+    tst     r3, #0x8                   \n\
+    bne     VoltageChange_loop         \n\
+                                       \n\
+    subs    r1, r1, #1         @ update conditional execution counter\n\
+    beq     retry":"=&r"(unused)
+                            :"r"(&CCCR), "r"(ramstart)
+                            :"r0", "r1", "r3");
+
+       local_irq_restore(flags);
+
+}
+
+static void clr_all_sqc(void)
+{
+       int i = 0;
+       for (i = 0; i < 32; i++)
+               PCMD(i) &= ~PCMD_SQC;
+}
+
+static void clr_all_mbc(void)
+{
+       int i = 0;
+       for (i = 0; i < 32; i++)
+               PCMD(i) &= ~PCMD_MBC;
+}
+
+static void clr_all_dce(void)
+{
+       int i = 0;
+       for (i = 0; i < 32; i++)
+               PCMD(i) &= ~PCMD_DCE;
+}
+
+static void set_mbc_bit(int ReadPointer, int NumOfBytes)
+{
+       PCMD0 |= PCMD_MBC;
+       PCMD1 |= PCMD_MBC;
+}
+
+static void set_lc_bit(int ReadPointer, int NumOfBytes)
+{
+       PCMD0 |= PCMD_LC;
+       PCMD1 |= PCMD_LC;
+       PCMD2 |= PCMD_LC;
+}
+
+static void set_cmd_data(unsigned char *DataArray, int StartPoint, int size)
+{
+       PCMD0 &= 0xFFFFFF00;
+       PCMD0 |= DataArray[0];
+       PCMD1 &= 0xFFFFFF00;
+       PCMD1 |= DataArray[1];
+       PCMD2 &= 0xFFFFFF00;
+       PCMD2 |= DataArray[2];
+}
+
+/* coupled indicates that this VCS is to be coupled with a FCS */
+static void power_change_cmd(unsigned int DACValue, int coupled)
+{
+       unsigned char dataArray[3];
+
+       dataArray[0] = 0;                               /* Command 0 */
+       dataArray[1] = (DACValue & 0x000000FF);         /* data LSB */
+       dataArray[2] = (DACValue & 0x0000FF00) >> 8;    /* data MSB */
+
+       PVCR = 0;
+
+       PCFR &= ~PCFR_FVC;
+       PVCR &= 0xFFFFF07F;     /*      no delay is necessary   */
+       PVCR &= 0xFFFFFF80;     /*  clear slave address         */
+       PVCR |= 0x20;           /*      set slave address       */
+
+       PVCR &= 0xFE0FFFFF;     /*      clear read pointer 0    */
+       PVCR |= 0;
+
+       /*  DCE and SQC are not necessary for single command */
+       clr_all_sqc();
+       clr_all_dce();
+
+       clr_all_mbc();
+       set_mbc_bit(0, 2);
+
+       /*  indicate the last byte of this command is holded in this register */
+       PCMD2 &= ~PCMD_MBC;
+
+       /*  indicate this is the first command and last command also        */
+       set_lc_bit(0, 3);
+
+       /*  programming the command data bit        */
+       set_cmd_data(dataArray, 0, 2);
+
+       /* Enable Power I2C */
+       PCFR |= PCFR_PI2CEN;
+
+       if (coupled) {
+               /* Enable Power I2C and FVC */
+               PCFR |= PCFR_FVC;
+       }
+}
Index: linux-2.6.17/include/asm-arm/arch-pxa/pxa-regs.h
===================================================================
--- linux-2.6.17.orig/include/asm-arm/arch-pxa/pxa-regs.h
+++ linux-2.6.17/include/asm-arm/arch-pxa/pxa-regs.h
@@ -2042,6 +2042,14 @@
 #define MDMRS          __REG(0x48000040)  /* MRS value to be written
to SDRAM */
 #define BOOT_DEF       __REG(0x48000044)  /* Read-Only Boot-Time
Register. Contains BOOT_SEL and PKG_SEL */

+#define MDREFR_DRI 0xFFF
+#define MSC0_RDF (0xF << 20)
+#define MSC0_RDN (0xF << 24)
+#define MSC0_RRR (0x7 << 12)
+#define MDREFR_RFU 0xC0200000
+#define MDCNFG_DTC0 (0x3 << 8)
+#define MDCNFG_DTC2 (0x3 << 24)
+
 /*
  * More handy macros for PCMCIA
  *
Index: linux-2.6.17/include/asm-arm/arch-pxa/oppoint.h
===================================================================
--- /dev/null
+++ linux-2.6.17/include/asm-arm/arch-pxa/oppoint.h
@@ -0,0 +1,119 @@
+/*
+ * include/asm-arm/arch-pxa/oppoint.h
+ *
+ * Bulverde-specific definitions for OpPoint.  If further PXA boards are
+ * supported in the future, will split into board-specific files.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ * Copyright (C) 2002, 2006 MontaVista Software <source@mvista.com>
+ *
+ * Based on arch/ppc/platforms/ibm405lp_dpm.h by Bishop Brock.
+ */
+
+#ifndef __ASM_ARM_PXA_POWEROP_H__
+#define __ASM_ARM_PXA_POWEROP_H__
+
+#ifdef __KERNEL__
+#ifndef __ASSEMBLER__
+#include <linux/config.h>
+#include <linux/notifier.h>
+#include <linux/ioctl.h>
+#include <linux/miscdevice.h>
+
+#define CCLKCFG_TURBO   0x1
+#define CCLKCFG_FCS     0x2
+
+#define L_NUM   31              /*  30 different L numbers. */
+#define N_NUM   7               /*  7 N numbers. */
+
+#define BLVD_MIN_FREQ       13000
+/* latest PowerPoint documentation indicates 624000, not 540000*/
+#define BLVD_MAX_FREQ       624000
+
+void mainstone_set_freq(unsigned int);
+
+int mainstone_clk_init(void);
+unsigned int mainstone_read_clkcfg(void);
+void mainstone_freq_cleanup(void);
+
+#define BLVD_MAX_VOL_C5        1500    /*  in mV.  */
+#define BLVD_MIN_VOL_C5        899     /*  in Mv.  */
+#define BLVD_MAX_VOL_C0        1400    /*  in mV.  */
+#define BLVD_MIN_VOL_C0        850     /*  in Mv.  */
+
+unsigned int mv2DAC(unsigned int mv);
+void vm_setvoltage(unsigned int);
+unsigned int mainstone_validate_voltage(unsigned int mv);
+
+void mainstone_set_voltage(unsigned int mv);
+void mainstone_prep_set_voltage(unsigned int mv);
+int mainstone_vcs_init(void);
+
+void mainstone_set_freq(unsigned int);
+
+int mainstone_clk_init(void);
+unsigned int mainstone_read_clkcfg(void);
+void mainstone_freq_cleanup(void);
+
+enum {
+       CPUMODE_RUN,
+       CPUMODE_IDLE,
+       CPUMODE_STANDBY,
+       CPUMODE_SLEEP,
+       CPUMODE_RESERVED,
+       CPUMODE_SENSE,
+       CPUMODE_RESERVED2,
+       CPUMODE_DEEPSLEEP,
+};
+
+#define PM_SUSPEND_DEEP        ((__force suspend_state_t) 2)
+
+struct oppoint_regs {
+       unsigned int    cccr;
+       unsigned int    clkcfg;
+       unsigned int    voltage;        /*This is not a register.*/
+};
+
+/*
+ * Instances of this structure define valid Bulverde operating points for DPM.
+ * Voltages are represented in mV, and frequencies are represented in KHz.
+ */
+
+struct md_opt {
+       /* Specified values */
+        int v;         /* Target voltage in mV*/
+        int l;         /* Run Mode to Oscillator ratio */
+        int n;         /* Turbo-Mode to Run-Mode ratio */
+        int b;         /* Fast Bus Mode */
+        int half_turbo;/* Half Turbo bit */
+        int cccra;     /* the 'A' bit of the CCCR register,
+                         alternate MEMC clock */
+       int cpll_enabled; /* core PLL is ON?  (Bulverde >="C0" feature)*/
+       int ppll_enabled; /* peripherial PLL is ON? (Bulverde >="C0" feature)*/
+
+       int sleep_mode;
+        /*Calculated values*/
+       unsigned int lcd;       /*in KHz  */
+       unsigned int lpj;       /*New value for loops_per_jiffy */
+       unsigned int cpu;       /*CPU frequency in KHz */
+       unsigned int turbo;     /* Turbo bit in clkcfg */
+
+       struct oppoint_regs regs;   /* Register values */
+};
+
+#endif /* __ASSEMBLER__ */
+#endif /* __KERNEL__ */
+#endif
Index: linux-2.6.17/arch/arm/mach-pxa/mainstone_oppoint.c
===================================================================
--- /dev/null
+++ linux-2.6.17/arch/arm/mach-pxa/mainstone_oppoint.c
@@ -0,0 +1,1910 @@
+/*
+ * arch/arm/mach-pxa/mainstone_oppoint.c  PM support for Intel PXA27x
+ *
+ * Author: <source@mvista.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ * Copyright (C) 2002, 2005, 2006 MontaVista Software <source@mvista.com>.
+ *
+ * Based on code by Matthew Locke, Dmitry Chigirev, and Bishop Brock.
+ */
+#define DEBUG
+#include <linux/config.h>
+
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/pm.h>
+
+#include <linux/proc_fs.h>
+#include <linux/delay.h>
+#include <linux/cpufreq.h>
+
+#include <asm/uaccess.h>
+
+#include <asm/hardware.h>
+#include <asm/arch/oppoint.h>
+#include <asm/arch/pxa-regs.h>
+
+static int saved_loops_per_jiffy = 0;
+static int saved_cpu_freq = 0;
+
+#define BULVERDE_DEFAULT_VOLTAGE 1400
+
+#define FSCALER_NOP         0
+#define FSCALER_CPUFREQ        (1 << 0)
+#define FSCALER_SLEEP    (1 << 1)
+#define FSCALER_STANDBY        (1 << 2)
+#define FSCALER_DEEPSLEEP      (1 << 3)
+#define FSCALER_WAKEUP  (1 << 4)
+#define FSCALER_VOLTAGE        (1 << 5)
+#define FSCALER_XPLLON   (1 << 6)
+#define FSCALER_HALFTURBO_ON   (1 << 7)
+#define FSCALER_HALFTURBO_OFF  (1 << 8)
+#define FSCALER_TURBO_ON       (1 << 9)
+#define FSCALER_TURBO_OFF      (1 << 10)
+
+#define FSCALER_TURBO (FSCALER_TURBO_ON | FSCALER_TURBO_OFF)
+
+#define FSCALER_ANY_SLEEPMODE     (FSCALER_SLEEP | \
+                                  FSCALER_STANDBY | \
+                                  FSCALER_DEEPSLEEP)
+
+#define CCCR_CPDIS_BIT_ON        (1 << 31)
+#define CCCR_PPDIS_BIT_ON        (1 << 30)
+#define CCCR_CPDIS_BIT_OFF      (0 << 31)
+#define CCCR_PPDIS_BIT_OFF      (0 << 30)
+#define CCCR_PLL_EARLY_EN_BIT_ON   (1 << 26)
+#define CCSR_CPLL_LOCKED          (1 << 29)
+#define CCSR_PPLL_LOCKED          (1 << 28)
+
+/* CLKCFG
+   | 31------------------------------------------- | 3 | 2  | 1 | 0 |
+   | --------------------------------------------- | B | HT | F | T |
+*/
+#define CLKCFG_B_BIT          (1 << 3)
+#define CLKCFG_HT_BIT        (1 << 2)
+#define CLKCFG_F_BIT          (1 << 1)
+#define CLKCFG_T_BIT          1
+
+/* Initialize the machine-dependent operating point from a list of parameters,
+   which has already been installed in the pp field of the operating point.
+   Some of the parameters may be specified with a value of -1 to indicate a
+   default value. */
+
+#define        PLL_L_MAX       31
+#define        PLL_N_MAX       8
+
+/* The MIN for L is 2 in the Yellow Book tables, but L=1 really means
+   13M mode, so L min includes 1 */
+#define        PLL_L_MIN       1
+#define        PLL_N_MIN       2
+
+/* memory timing (MSC0,DTC,DRI) constants (see Blob and Intel BBU sources) */
+#define XLLI_MSC0_13 0x11101110
+#define XLLI_MSC0_19 0x11101110
+#define XLLI_MSC0_26 0x11201120  /* 26 MHz setting */
+#define XLLI_MSC0_32 0x11201120
+#define XLLI_MSC0_39 0x11301130   /* 39 MHz setting */
+#define XLLI_MSC0_45 0x11301130
+#define XLLI_MSC0_52 0x11401140  /* @ 52 MHz setting */
+#define XLLI_MSC0_58 0x11401140
+#define XLLI_MSC0_65 0x11501150  /* @ 65 MHz setting */
+#define XLLI_MSC0_68 0x11501150
+#define XLLI_MSC0_71 0x11501150  /* @ 71.5 MHz setting */
+#define XLLI_MSC0_74 0x11601160
+#define XLLI_MSC0_78 0x12601260  /* @ 78 MHz setting */
+#define XLLI_MSC0_81 0x12601260
+#define XLLI_MSC0_84 0x12601260  /*  @ 84.5 MHz setting */
+#define XLLI_MSC0_87 0x12701270
+#define XLLI_MSC0_91 0x12701270  /* 91 MHz setting */
+#define XLLI_MSC0_94 0x12701270  /* 94.2 MHz setting */
+#define XLLI_MSC0_97 0x12701270  /* 97.5 MHz setting */
+#define XLLI_MSC0_100 0x12801280 /* 100.7 MHz setting */
+#define XLLI_MSC0_104 0x12801280 /* 104 MHz setting */
+#define XLLI_MSC0_110 0x12901290
+#define XLLI_MSC0_117 0x13901390 /* 117 MHz setting */
+#define XLLI_MSC0_124 0x13A013A0
+#define XLLI_MSC0_130 0x13A013A0 /* 130 MHz setting */
+#define XLLI_MSC0_136 0x13B013B0
+#define XLLI_MSC0_143 0x13B013B0
+#define XLLI_MSC0_149 0x13C013C0
+#define XLLI_MSC0_156 0x14C014C0
+#define XLLI_MSC0_162 0x14C014C0
+#define XLLI_MSC0_169 0x14C014C0
+#define XLLI_MSC0_175 0x14C014C0
+#define XLLI_MSC0_182 0x14C014C0
+#define XLLI_MSC0_188 0x14C014C0
+#define XLLI_MSC0_195 0x15C015C0
+#define XLLI_MSC0_201 0x15D015D0
+#define XLLI_MSC0_208 0x15D015D0
+
+/* DTC settings depend on 16/32 bit SDRAM we have (32 is chosen) */
+#define XLLI_DTC_13 0x00000000
+#define XLLI_DTC_19 0x00000000
+#define XLLI_DTC_26 0x00000000
+#define XLLI_DTC_32 0x00000000
+#define XLLI_DTC_39 0x00000000
+#define XLLI_DTC_45 0x00000000
+#define XLLI_DTC_52 0x00000000
+#define XLLI_DTC_58 0x01000100
+#define XLLI_DTC_65 0x01000100
+#define XLLI_DTC_68 0x01000100
+#define XLLI_DTC_71 0x01000100
+#define XLLI_DTC_74 0x01000100
+#define XLLI_DTC_78 0x01000100
+#define XLLI_DTC_81 0x01000100
+#define XLLI_DTC_84 0x01000100
+#define XLLI_DTC_87 0x01000100
+#define XLLI_DTC_91 0x02000200
+#define XLLI_DTC_94 0x02000200
+#define XLLI_DTC_97 0x02000200
+#define XLLI_DTC_100 0x02000200
+#define XLLI_DTC_104 0x02000200
+/* 110-208 MHz setting - SDCLK Halved*/
+#define XLLI_DTC_110 0x01000100
+#define XLLI_DTC_117 0x01000100
+#define XLLI_DTC_124 0x01000100
+#define XLLI_DTC_130 0x01000100
+#define XLLI_DTC_136 0x01000100
+#define XLLI_DTC_143 0x01000100
+#define XLLI_DTC_149 0x01000100
+#define XLLI_DTC_156 0x01000100
+#define XLLI_DTC_162 0x01000100
+#define XLLI_DTC_169 0x01000100
+#define XLLI_DTC_175 0x01000100
+/*  182-208 MHz setting - SDCLK Halved - Close to edge, so bump up */
+#define XLLI_DTC_182 0x02000200
+#define XLLI_DTC_188 0x02000200
+#define XLLI_DTC_195 0x02000200
+#define XLLI_DTC_201 0x02000200
+#define XLLI_DTC_208 0x02000200
+
+/*       Optimal values for DRI (refreash interval) settings for
+ * various MemClk settings (MDREFR)
+ */
+#define XLLI_DRI_13 0x002
+#define XLLI_DRI_19 0x003
+#define XLLI_DRI_26 0x005
+#define XLLI_DRI_32 0x006
+#define XLLI_DRI_39 0x008
+#define XLLI_DRI_45 0x00A
+#define XLLI_DRI_52 0x00B
+#define XLLI_DRI_58 0x00D
+#define XLLI_DRI_65 0x00E
+#define XLLI_DRI_68 0x00F
+#define XLLI_DRI_71 0x010
+#define XLLI_DRI_74 0x011
+#define XLLI_DRI_78 0x012
+#define XLLI_DRI_81 0x012
+#define XLLI_DRI_84 0x013
+#define XLLI_DRI_87 0x014
+#define XLLI_DRI_91 0x015
+#define XLLI_DRI_94 0x016
+#define XLLI_DRI_97 0x016
+#define XLLI_DRI_100 0x017
+#define XLLI_DRI_104 0x018
+#define XLLI_DRI_110 0x01A
+#define XLLI_DRI_117 0x01B
+#define XLLI_DRI_124 0x01D
+#define XLLI_DRI_130 0x01E
+#define XLLI_DRI_136 0x020
+#define XLLI_DRI_143 0x021
+#define XLLI_DRI_149 0x023
+#define XLLI_DRI_156 0x025
+#define XLLI_DRI_162 0x026
+#define XLLI_DRI_169 0x028
+#define XLLI_DRI_175 0x029
+#define XLLI_DRI_182 0x02B
+#define XLLI_DRI_188 0x02D
+#define XLLI_DRI_195 0x02E
+#define XLLI_DRI_201 0x030
+#define XLLI_DRI_208 0x031
+
+
+
+/* timings for memory controller set up (masked values) */
+struct mem_timings{
+       unsigned int msc0; /* for MSC0 */
+       unsigned int dtc; /* for MDCNFG */
+       unsigned int dri; /* for MDREFR */
+};
+
+static int pxa27x_transition(struct oppoint *cur, struct oppoint *new);
+
+static struct oppoint m13 = {
+       .name = "13m",
+       .type = PM_FREQ_CHANGE,
+       .prepare_transition  = cpufreq_prepare_transition,
+       .transition = pxa27x_transition,
+       .finish_transition = cpufreq_finish_transition,
+};
+
+static struct oppoint mext13 = {
+       .name = "13mext",
+       .type = PM_FREQ_CHANGE,
+       .voltage = 1500,
+       .prepare_transition  = cpufreq_prepare_transition,
+       .transition = pxa27x_transition,
+       .finish_transition = cpufreq_finish_transition,
+};
+
+static struct oppoint sleep = {
+       .name = "sleep",
+       .type = PM_FREQ_CHANGE,
+       .voltage = 1500,
+       .frequency = 0,
+       .latency = 150,
+       .prepare_transition  = cpufreq_prepare_transition,
+       .transition = pxa27x_transition,
+       .finish_transition = cpufreq_finish_transition,
+};
+
+static struct oppoint deepsleep = {
+       .name = "deepsleep",
+       .type = PM_FREQ_CHANGE,
+       .voltage = 1500,
+       .frequency = 0,
+       .latency = 1000,
+       .prepare_transition  = cpufreq_prepare_transition,
+       .transition = pxa27x_transition,
+       .finish_transition = cpufreq_finish_transition,
+};
+
+static struct oppoint standby = {
+       .name = "pxastandby",
+       .type = PM_FREQ_CHANGE,
+       .voltage = 1500,
+       .frequency = 0,
+       .latency = 150,
+       .prepare_transition  = cpufreq_prepare_transition,
+       .transition = pxa27x_transition,
+       .finish_transition = cpufreq_finish_transition,
+};
+
+static struct oppoint lowest = {
+       .name = "lowest",
+       .type = PM_FREQ_CHANGE,
+       .frequency = 0,
+       .voltage = 0,
+       .latency = 100,
+       .prepare_transition  = cpufreq_prepare_transition,
+       .transition = pxa27x_transition,
+       .finish_transition = cpufreq_finish_transition,
+};
+
+static struct oppoint low = {
+       .name = "low",
+       .type = PM_FREQ_CHANGE,
+       .frequency = 0,
+       .voltage = 0,
+       .latency = 100,
+       .prepare_transition  = cpufreq_prepare_transition,
+       .transition = pxa27x_transition,
+       .finish_transition = cpufreq_finish_transition,
+};
+
+static struct oppoint mediumlow = {
+       .name = "mediumlow",
+       .type = PM_FREQ_CHANGE,
+       .frequency = 0,
+       .voltage = 0,
+       .latency = 100,
+       .prepare_transition  = cpufreq_prepare_transition,
+       .transition = pxa27x_transition,
+       .finish_transition = cpufreq_finish_transition,
+};
+
+static struct oppoint medium = {
+       .name = "medium",
+       .type = PM_FREQ_CHANGE,
+       .frequency = 0,
+       .voltage = 0,
+       .latency = 100,
+       .prepare_transition  = cpufreq_prepare_transition,
+       .transition = pxa27x_transition,
+       .finish_transition = cpufreq_finish_transition,
+};
+
+static struct oppoint mediumhigh = {
+       .name = "mediumhigh",
+       .type = PM_FREQ_CHANGE,
+       .frequency = 0,
+       .voltage = 0,
+       .latency = 100,
+       .prepare_transition  = cpufreq_prepare_transition,
+       .transition = pxa27x_transition,
+       .finish_transition = cpufreq_finish_transition,
+};
+
+static struct oppoint high = {
+       .name = "high",
+       .type = PM_FREQ_CHANGE,
+       .frequency = 0,
+       .voltage = 0,
+       .latency = 100,
+       .prepare_transition  = cpufreq_prepare_transition,
+       .transition = pxa27x_transition,
+       .finish_transition = cpufreq_finish_transition,
+};
+
+static struct oppoint highest = {
+       .name = "highest",
+       .type = PM_FREQ_CHANGE,
+       .frequency = 0,
+       .voltage = 0,
+       .latency = 100,
+       .prepare_transition  = cpufreq_prepare_transition,
+       .transition = pxa27x_transition,
+       .finish_transition = cpufreq_finish_transition,
+};
+
+static struct md_opt mhz104 = {
+       .v = 900,
+       .l = 8,
+       .n = 2,
+       .b = 1,
+       .half_turbo = 0,
+       .cccra = 1,
+       .cpll_enabled = 1,
+       .ppll_enabled = 1,
+       .sleep_mode = 0,
+};
+
+static struct md_opt mhz208 = {
+       .v = 1050,
+       .l = 16,
+       .n = 2,
+       .b = 1,
+       .half_turbo = 0,
+       .cccra = 0,
+       .cpll_enabled = 1,
+       .ppll_enabled = 1,
+       .sleep_mode = 0,
+};
+
+static struct md_opt mhz312 = {
+       .v = 1250,
+       .l = 16,
+       .n = 3,
+       .b = 1,
+       .half_turbo = 0,
+       .cccra = 0,
+       .cpll_enabled = 1,
+       .ppll_enabled = 1,
+       .sleep_mode = 0,
+};
+
+static struct md_opt mhz208hi = {
+       .v = 1150,
+       .l = 16,
+       .n = 2,
+       .b = 1,
+       .half_turbo = 0,
+       .cccra = 1,
+       .cpll_enabled = 1,
+       .ppll_enabled = 1,
+       .sleep_mode = 0,
+};
+
+static struct md_opt mhz312hi = {
+       .v = 1250,
+       .l = 16,
+       .n = 3,
+       .b = 1,
+       .half_turbo = 0,
+       .cccra = 1,
+       .cpll_enabled = 1,
+       .ppll_enabled = 1,
+       .sleep_mode = 0,
+};
+
+static struct md_opt mhz416hi = {
+       .v = 1350,
+       .l = 16,
+       .n = 4,
+       .b = 1,
+       .half_turbo = 0,
+       .cccra = 1,
+       .cpll_enabled = 1,
+       .ppll_enabled = 1,
+       .sleep_mode = 0,
+};
+
+static struct md_opt mhz520hi = {
+       .v = 1450,
+       .l = 16,
+       .n = 5,
+       .b = 1,
+       .half_turbo = 0,
+       .cccra = 1,
+       .cpll_enabled = 1,
+       .ppll_enabled = 1,
+       .sleep_mode = 0,
+};
+
+static struct md_opt md_sleep = {
+       .v = 1500,
+       .l = 0,
+       .n = 0,
+       .b = 0,
+       .half_turbo = -1,
+       .cccra = 0,
+       .cpll_enabled = 0,
+       .ppll_enabled = 0,
+       .sleep_mode = 3,
+};
+
+static struct md_opt md_deepsleep = {
+       .v = 1500,
+       .l = 0,
+       .n = 0,
+       .b = 0,
+       .half_turbo = -1,
+       .cccra = 0,
+       .cpll_enabled = 0,
+       .ppll_enabled = 0,
+       .sleep_mode = 7,
+};
+
+static struct md_opt md_standby = {
+       .v = 1500,
+       .l = 1,
+       .n = 2,
+       .b = 0,
+       .half_turbo = -1,
+       .cccra = 0,
+       .cpll_enabled = 0,
+       .ppll_enabled = 0,
+       .sleep_mode = -1,
+};
+
+static struct md_opt md_13m = {
+       .v = 1500,
+       .l = 1,
+       .n = 2,
+       .b = 0,
+       .half_turbo = -1,
+       .cccra = 0,
+       .cpll_enabled = 0,
+       .ppll_enabled = 0,
+       .sleep_mode = -1,
+};
+
+static struct md_opt md_13mext = {
+       .v = 1500,
+       .l = 1,
+       .n = 2,
+       .b = 0,
+       .half_turbo = -1,
+       .cccra = 0,
+       .cpll_enabled = 0,
+       .ppll_enabled = 0,
+       .sleep_mode = -1,
+};
+
+static void
+mainstone_setup_opt(struct oppoint *op, uint freq, struct md_opt *md)
+{
+       op->frequency = freq * 1000;
+       op->md_data = (void *)md;
+       op->voltage = md->v;
+}
+
+static unsigned int fscaler_flags = 0;
+
+void mainstone_fully_define_opt(struct oppoint *cur,
+                                  struct oppoint *new);
+static int mainstone_fscale(struct oppoint *cur, struct oppoint *new);
+static void mainstone_fscaler(struct oppoint_regs *regs);
+
+extern void mainstone_set_voltage(unsigned int mv);
+extern void mainstone_prep_set_voltage(unsigned int mv);
+extern int mainstone_vcs_init(void);
+extern void mainstone_voltage_cleanup(void);
+
+static unsigned long
+calculate_memclk(unsigned long cccr, unsigned long clkcfg)
+{
+       unsigned long M, memclk;
+       u32 L;
+
+       L = cccr & 0x1f;
+       if (cccr & (1 << 25)) {
+               if  (clkcfg & CLKCFG_B_BIT)
+                       memclk = (L*13);
+               else
+                       memclk = (L*13)/2;
+       }
+       else {
+               if (L <= 10) M = 1;
+               else if (L <= 20) M = 2;
+               else M = 4;
+
+               memclk = (L*13)/M;
+       }
+
+       return memclk;
+}
+
+static unsigned long
+calculate_new_memclk(struct oppoint_regs *regs)
+{
+       return calculate_memclk(regs->cccr, regs->clkcfg);
+}
+
+static unsigned long
+calculate_cur_memclk(void)
+{
+       unsigned long cccr = CCCR;
+       return calculate_memclk(cccr, mainstone_read_clkcfg());
+}
+
+/* Returns optimal timings for memory controller
+ * a - [A]
+ * b - [B]
+ * l - value of L
+ */
+static struct mem_timings get_optimal_mem_timings(int a, int b, int l){
+       struct mem_timings ret = {
+               .msc0 = 0,
+               .dtc = 0,
+               .dri = 0,
+       };
+
+       if (a!=0 && b==0) {
+               switch (l) {
+               case 2:
+                       ret.msc0 = XLLI_MSC0_13;
+                       ret.dtc = XLLI_DTC_13;
+                       ret.dri = XLLI_DRI_13;
+                       break;
+               case 3:
+                       ret.msc0 = XLLI_MSC0_19;
+                       ret.dtc = XLLI_DTC_19;
+                       ret.dri = XLLI_DRI_19;
+                       break;
+               case 4:
+                       ret.msc0 = XLLI_MSC0_26;
+                       ret.dtc = XLLI_DTC_26;
+                       ret.dri = XLLI_DRI_26;
+                       break;
+               case 5:
+                       ret.msc0 = XLLI_MSC0_32;
+                       ret.dtc = XLLI_DTC_32;
+                       ret.dri = XLLI_DRI_32;
+                       break;
+               case 6:
+                       ret.msc0 = XLLI_MSC0_39;
+                       ret.dtc = XLLI_DTC_39;
+                       ret.dri = XLLI_DRI_39;
+                       break;
+               case 7:
+                       ret.msc0 = XLLI_MSC0_45;
+                       ret.dtc = XLLI_DTC_45;
+                       ret.dri = XLLI_DRI_45;
+                       break;
+               case 8:
+                       ret.msc0 = XLLI_MSC0_52;
+                       ret.dtc = XLLI_DTC_52;
+                       ret.dri = XLLI_DRI_52;
+                       break;
+               case 9:
+                       ret.msc0 = XLLI_MSC0_58;
+                       ret.dtc = XLLI_DTC_58;
+                       ret.dri = XLLI_DRI_58;
+                       break;
+               case 10:
+                       ret.msc0 = XLLI_MSC0_65;
+                       ret.dtc = XLLI_DTC_65;
+                       ret.dri = XLLI_DRI_65;
+                       break;
+                       /*
+                        *       L11 - L20 ARE THE SAME for A0Bx
+                        */
+               case 11:
+                       ret.msc0 = XLLI_MSC0_71;
+                       ret.dtc = XLLI_DTC_71;
+                       ret.dri = XLLI_DRI_71;
+                       break;
+               case 12:
+                       ret.msc0 = XLLI_MSC0_78;
+                       ret.dtc = XLLI_DTC_78;
+                       ret.dri = XLLI_DRI_78;
+                       break;
+               case 13:
+                       ret.msc0 = XLLI_MSC0_84;
+                       ret.dtc = XLLI_DTC_84;
+                       ret.dri = XLLI_DRI_84;
+                       break;
+               case 14:
+                       ret.msc0 = XLLI_MSC0_91;
+                       ret.dtc = XLLI_DTC_91;
+                       ret.dri = XLLI_DRI_91;
+                       break;
+               case 15:
+                       ret.msc0 = XLLI_MSC0_97;
+                       ret.dtc = XLLI_DTC_97;
+                       ret.dri = XLLI_DRI_97;
+                       break;
+               case 16:
+                       ret.msc0 = XLLI_MSC0_104;
+                       ret.dtc = XLLI_DTC_104;
+                       ret.dri = XLLI_DRI_104;
+                       break;
+               case 17:
+                       ret.msc0 = XLLI_MSC0_110;
+                       ret.dtc = XLLI_DTC_110;
+                       ret.dri = XLLI_DRI_110;
+                       break;
+               case 18:
+                       ret.msc0 = XLLI_MSC0_117;
+                       ret.dtc = XLLI_DTC_117;
+                       ret.dri = XLLI_DRI_117;
+                       break;
+               case 19:
+                       ret.msc0 = XLLI_MSC0_124;
+                       ret.dtc = XLLI_DTC_124;
+                       ret.dri = XLLI_DRI_124;
+                       break;
+               case 20:
+                       ret.msc0 = XLLI_MSC0_130;
+                       ret.dtc = XLLI_DTC_130;
+                       ret.dri = XLLI_DRI_130;
+                       break;
+               case 21:
+                       ret.msc0 = XLLI_MSC0_136;
+                       ret.dtc = XLLI_DTC_136;
+                       ret.dri = XLLI_DRI_136;
+                       break;
+               case 22:
+                       ret.msc0 = XLLI_MSC0_143;
+                       ret.dtc = XLLI_DTC_143;
+                       ret.dri = XLLI_DRI_143;
+                       break;
+               case 23:
+                       ret.msc0 = XLLI_MSC0_149;
+                       ret.dtc = XLLI_DTC_149;
+                       ret.dri = XLLI_DRI_149;
+                       break;
+               case 24:
+                       ret.msc0 = XLLI_MSC0_156;
+                       ret.dtc = XLLI_DTC_156;
+                       ret.dri = XLLI_DRI_156;
+                       break;
+               case 25:
+                       ret.msc0 = XLLI_MSC0_162;
+                       ret.dtc = XLLI_DTC_162;
+                       ret.dri = XLLI_DRI_162;
+                       break;
+               case 26:
+                       ret.msc0 = XLLI_MSC0_169;
+                       ret.dtc = XLLI_DTC_169;
+                       ret.dri = XLLI_DRI_169;
+                       break;
+               case 27:
+                       ret.msc0 = XLLI_MSC0_175;
+                       ret.dtc = XLLI_DTC_175;
+                       ret.dri = XLLI_DRI_175;
+                       break;
+               case 28:
+                       ret.msc0 = XLLI_MSC0_182;
+                       ret.dtc = XLLI_DTC_182;
+                       ret.dri = XLLI_DRI_182;
+                       break;
+               case 29:
+                       ret.msc0 = XLLI_MSC0_188;
+                       ret.dtc = XLLI_DTC_188;
+                       ret.dri = XLLI_DRI_188;
+                       break;
+               case 30:
+                       ret.msc0 = XLLI_MSC0_195;
+                       ret.dtc = XLLI_DTC_195;
+                       ret.dri = XLLI_DRI_195;
+                       break;
+               case 31:
+                       ret.msc0 = XLLI_MSC0_201;
+                       ret.dtc = XLLI_DTC_201;
+                       ret.dri = XLLI_DRI_201;
+               }
+
+       } else if (a!=0 && b!=0) {
+         switch (l) {
+               case 2:
+                       ret.msc0 = XLLI_MSC0_26;
+                       ret.dtc = XLLI_DTC_26;
+                       ret.dri = XLLI_DRI_26;
+                       break;
+               case 3:
+                       ret.msc0 = XLLI_MSC0_39;
+                       ret.dtc = XLLI_DTC_39;
+                       ret.dri = XLLI_DRI_39;
+                       break;
+               case 4:
+                       ret.msc0 = XLLI_MSC0_52;
+                       ret.dtc = XLLI_DTC_52;
+                       ret.dri = XLLI_DRI_52;
+                       break;
+               case 5:
+                       ret.msc0 = XLLI_MSC0_65;
+                       ret.dtc = XLLI_DTC_65;
+                       ret.dri = XLLI_DRI_65;
+                       break;
+               case 6:
+                       ret.msc0 = XLLI_MSC0_78;
+                       ret.dtc = XLLI_DTC_78;
+                       ret.dri = XLLI_DRI_78;
+                       break;
+               case 7:
+                       ret.msc0 = XLLI_MSC0_91;
+                       ret.dtc = XLLI_DTC_91;
+                       ret.dri = XLLI_DRI_91;
+                       break;
+               case 8:
+                       ret.msc0 = XLLI_MSC0_104;
+                       ret.dtc = XLLI_DTC_104;
+                       ret.dri = XLLI_DRI_104;
+                       break;
+               case 9:
+                       ret.msc0 = XLLI_MSC0_117;
+                       ret.dtc = XLLI_DTC_117;
+                       ret.dri = XLLI_DRI_117;
+                       break;
+               case 10:
+                       ret.msc0 = XLLI_MSC0_130;
+                       ret.dtc = XLLI_DTC_130;
+                       ret.dri = XLLI_DRI_130;
+                       break;
+               case 11:
+                       ret.msc0 = XLLI_MSC0_143;
+                       ret.dtc = XLLI_DTC_143;
+                       ret.dri = XLLI_DRI_143;
+                       break;
+               case 12:
+                       ret.msc0 = XLLI_MSC0_156;
+                       ret.dtc = XLLI_DTC_156;
+                       ret.dri = XLLI_DRI_156;
+                       break;
+               case 13:
+                       ret.msc0 = XLLI_MSC0_169;
+                       ret.dtc = XLLI_DTC_169;
+                       ret.dri = XLLI_DRI_169;
+                       break;
+               case 14:
+                       ret.msc0 = XLLI_MSC0_182;
+                       ret.dtc = XLLI_DTC_182;
+                       ret.dri = XLLI_DRI_182;
+                       break;
+               case 15:
+                       ret.msc0 = XLLI_MSC0_195;
+                       ret.dtc = XLLI_DTC_195;
+                       ret.dri = XLLI_DRI_195;
+                       break;
+               case 16:
+                       ret.msc0 = XLLI_MSC0_208;
+                       ret.dtc = XLLI_DTC_208;
+                       ret.dri = XLLI_DRI_208;
+               }
+       } else {
+         /* A0Bx */
+               switch (l) {
+               case 2:
+                       ret.msc0 = XLLI_MSC0_26;
+                       ret.dtc = XLLI_DTC_26;
+                       ret.dri = XLLI_DRI_26;
+                       break;
+               case 3:
+                       ret.msc0 = XLLI_MSC0_39;
+                       ret.dtc = XLLI_DTC_39;
+                       ret.dri = XLLI_DRI_39;
+                       break;
+               case 4:
+                       ret.msc0 = XLLI_MSC0_52;
+                       ret.dtc = XLLI_DTC_52;
+                       ret.dri = XLLI_DRI_52;
+                       break;
+               case 5:
+                       ret.msc0 = XLLI_MSC0_65;
+                       ret.dtc = XLLI_DTC_65;
+                       ret.dri = XLLI_DRI_65;
+                       break;
+               case 6:
+                       ret.msc0 = XLLI_MSC0_78;
+                       ret.dtc = XLLI_DTC_78;
+                       ret.dri = XLLI_DRI_78;
+                       break;
+               case 7:
+                       ret.msc0 = XLLI_MSC0_91;
+                       ret.dtc = XLLI_DTC_91;
+                       ret.dri = XLLI_DRI_91;
+                       break;
+               case 8:
+                       ret.msc0 = XLLI_MSC0_104;
+                       ret.dtc = XLLI_DTC_104;
+                       ret.dri = XLLI_DRI_104;
+                       break;
+               case 9:
+                       ret.msc0 = XLLI_MSC0_117;
+                       ret.dtc = XLLI_DTC_117;
+                       ret.dri = XLLI_DRI_117;
+                       break;
+               case 10:
+                       ret.msc0 = XLLI_MSC0_130;
+                       ret.dtc = XLLI_DTC_130;
+                       ret.dri = XLLI_DRI_130;
+                       break;
+               case 11:
+                       ret.msc0 = XLLI_MSC0_71;
+                       ret.dtc = XLLI_DTC_71;
+                       ret.dri = XLLI_DRI_71;
+                       break;
+               case 12:
+                       ret.msc0 = XLLI_MSC0_78;
+                       ret.dtc = XLLI_DTC_78;
+                       ret.dri = XLLI_DRI_78;
+                       break;
+               case 13:
+                       ret.msc0 = XLLI_MSC0_84;
+                       ret.dtc = XLLI_DTC_84;
+                       ret.dri = XLLI_DRI_84;
+                       break;
+               case 14:
+                       ret.msc0 = XLLI_MSC0_91;
+                       ret.dtc = XLLI_DTC_91;
+                       ret.dri = XLLI_DRI_91;
+                       break;
+               case 15:
+                       ret.msc0 = XLLI_MSC0_97;
+                       ret.dtc = XLLI_DTC_97;
+                       ret.dri = XLLI_DRI_97;
+                       break;
+               case 16:
+                       ret.msc0 = XLLI_MSC0_104;
+                       ret.dtc = XLLI_DTC_104;
+                       ret.dri = XLLI_DRI_104;
+                       break;
+               case 17:
+                       ret.msc0 = XLLI_MSC0_110;
+                       ret.dtc = XLLI_DTC_110;
+                       ret.dri = XLLI_DRI_110;
+                       break;
+               case 18:
+                       ret.msc0 = XLLI_MSC0_117;
+                       ret.dtc = XLLI_DTC_117;
+                       ret.dri = XLLI_DRI_117;
+                       break;
+               case 19:
+                       ret.msc0 = XLLI_MSC0_124;
+                       ret.dtc = XLLI_DTC_124;
+                       ret.dri = XLLI_DRI_124;
+                       break;
+               case 20:
+                       ret.msc0 = XLLI_MSC0_130;
+                       ret.dtc = XLLI_DTC_130;
+                       ret.dri = XLLI_DRI_130;
+                       break;
+               case 21:
+                       ret.msc0 = XLLI_MSC0_68;
+                       ret.dtc = XLLI_DTC_68;
+                       ret.dri = XLLI_DRI_68;
+                       break;
+               case 22:
+                       ret.msc0 = XLLI_MSC0_71;
+                       ret.dtc = XLLI_DTC_71;
+                       ret.dri = XLLI_DRI_71;
+                       break;
+               case 23:
+                       ret.msc0 = XLLI_MSC0_74;
+                       ret.dtc = XLLI_DTC_74;
+                       ret.dri = XLLI_DRI_74;
+                       break;
+               case 24:
+                       ret.msc0 = XLLI_MSC0_78;
+                       ret.dtc = XLLI_DTC_78;
+                       ret.dri = XLLI_DRI_78;
+                       break;
+               case 25:
+                       ret.msc0 = XLLI_MSC0_81;
+                       ret.dtc = XLLI_DTC_81;
+                       ret.dri = XLLI_DRI_81;
+                       break;
+               case 26:
+                       ret.msc0 = XLLI_MSC0_84;
+                       ret.dtc = XLLI_DTC_84;
+                       ret.dri = XLLI_DRI_84;
+                       break;
+               case 27:
+                       ret.msc0 = XLLI_MSC0_87;
+                       ret.dtc = XLLI_DTC_87;
+                       ret.dri = XLLI_DRI_87;
+                       break;
+               case 28:
+                       ret.msc0 = XLLI_MSC0_91;
+                       ret.dtc = XLLI_DTC_91;
+                       ret.dri = XLLI_DRI_91;
+                       break;
+               case 29:
+                       ret.msc0 = XLLI_MSC0_94;
+                       ret.dtc = XLLI_DTC_94;
+                       ret.dri = XLLI_DRI_94;
+                       break;
+               case 30:
+                       ret.msc0 = XLLI_MSC0_97;
+                       ret.dtc = XLLI_DTC_97;
+                       ret.dri = XLLI_DRI_97;
+                       break;
+               case 31:
+                       ret.msc0 = XLLI_MSC0_100;
+                       ret.dtc = XLLI_DTC_100;
+                       ret.dri = XLLI_DRI_100;
+               }
+       }
+
+       return ret;
+}
+
+static void assign_optimal_mem_timings(
+       unsigned int* msc0_reg,
+       unsigned int* mdrefr_reg,
+       unsigned int* mdcnfg_reg,
+       int a, int b, int l
+       )
+{
+       unsigned int msc0_reg_tmp = (*msc0_reg);
+       unsigned int mdrefr_reg_tmp = (*mdrefr_reg);
+       unsigned int mdcnfg_reg_tmp = (*mdcnfg_reg);
+       struct mem_timings timings = get_optimal_mem_timings(a,b,l);
+
+       /* clear bits which are set by get_optimal_mem_timings*/
+       msc0_reg_tmp &= ~(MSC0_RDF & MSC0_RDN & MSC0_RRR);
+       mdrefr_reg_tmp &= ~(MDREFR_RFU & MDREFR_DRI);
+       mdcnfg_reg_tmp &= ~(MDCNFG_DTC0 & MDCNFG_DTC2);
+
+       /* prepare appropriate timings */
+       msc0_reg_tmp |= timings.msc0;
+       mdrefr_reg_tmp |= timings.dri;
+       mdcnfg_reg_tmp |= timings.dtc;
+
+       /* set timings (all bits one time) */
+       (*msc0_reg) = msc0_reg_tmp;
+       (*mdrefr_reg) = mdrefr_reg_tmp;
+       (*mdcnfg_reg) = mdcnfg_reg_tmp;
+}
+
+static void set_mdrefr_value(u32 new_mdrefr)
+{
+       unsigned long s, old_mdrefr, errata62;
+       old_mdrefr = MDREFR;
+       /* E62 (28007106.pdf): Memory controller may hang while clearing
+        * MDREFR[K1DB2] or MDREFR[K2DB2]
+        */
+       errata62 = (((old_mdrefr & MDREFR_K1DB2) != 0) &&
+               ((new_mdrefr & MDREFR_K1DB2) == 0)) ||
+               (((old_mdrefr & MDREFR_K2DB2) != 0) &&
+               ((new_mdrefr & MDREFR_K2DB2) == 0));
+
+       if (errata62) {
+               unsigned long oscr_0 = OSCR;
+               unsigned long oscr_1 = oscr_0;
+               /* Step 1 - disable interrupts */
+               local_irq_save(s);
+               /* Step 2 - leave KxDB2, but set MDREFR[DRI] (bits 0-11) to
+                *  0xFFF
+                */
+               MDREFR = MDREFR | MDREFR_DRI;
+               /* Step 3 - read MDREFR one time */
+               MDREFR;
+               /* Step 4 - wait 1.6167us
+                * (3.25MHz clock increments OSCR0 7 times)
+                */
+               while (oscr_1-oscr_0 < 7) {
+                       cpu_relax();
+                       oscr_1 = OSCR;
+               }
+
+       }
+
+       /* Step 5 - clear K1DB1 and/or K2DB2, and set MDREFR[DRI] to
+        * proper value at the same time
+        */
+
+       /*Set MDREFR as if no errata workaround is needed*/
+       MDREFR = new_mdrefr;
+
+       if (errata62) {
+               /* Step 6 - read MDREFR one time*/
+               MDREFR;
+               /* Step 7 - enable interrupts*/
+               local_irq_restore(s);
+       }
+}
+
+static void mainstone_scale_cpufreq(struct oppoint_regs *regs)
+{
+       unsigned long new_memclk, cur_memclk;
+       u32 new_mdrefr, cur_mdrefr, read_mdrefr;
+       u32 new_msc0, new_mdcnfg;
+       int set_mdrefr = 0, scaling_up = 0;
+       int l, a, b;
+
+       l = regs->cccr & CCCR_L_MASK;   /* Get L */
+       b = (regs->clkcfg >> 3) & 0x1;
+       a = (regs->cccr >> 25) & 0x1;   /* cccr[A]: bit 25 */
+
+       cur_memclk = calculate_cur_memclk();
+       new_memclk = calculate_new_memclk(regs);
+
+       new_mdrefr = cur_mdrefr = MDREFR;
+       new_msc0 = MSC0;
+       new_mdcnfg = MDCNFG;
+
+       if (new_memclk != cur_memclk) {
+               /* SDCLK0,SDCLK1,SDCLK2 = MEMCLK - by default (<=52MHz) */
+               new_mdrefr &= ~( MDREFR_K0DB2 | MDREFR_K0DB4 |
+                       MDREFR_K1DB2 | MDREFR_K2DB2 );
+
+               if ((new_memclk > 52) && (new_memclk <= 104)) {
+                       /* SDCLK0 = MEMCLK/2, SDCLK1,SDCLK2 = MEMCLK */
+                       new_mdrefr |= MDREFR_K0DB2;
+               }
+               else if (new_memclk > 104){
+                       /* SDCLK0 = MEMCLK/4,  SDCLK1 and SDCLK2 = MEMCLK/2 */
+                       new_mdrefr |= (MDREFR_K0DB4 | MDREFR_K1DB2 |
MDREFR_K2DB2);
+               }
+
+               /* clock increasing or decreasing? */
+               if (new_memclk > cur_memclk) scaling_up = 1;
+       }
+
+       /* set MDREFR if necessary */
+       if (new_mdrefr != cur_mdrefr){
+               set_mdrefr = 1;
+               /* also adjust timings  as long as we change MDREFR value */
+               assign_optimal_mem_timings(
+                                          &new_msc0,
+                                          &new_mdrefr,
+                                          &new_mdcnfg,
+                                          a,b,l
+                                          );
+       }
+
+       /* if memclk is scaling up, set MDREFR before freq change
+        * (2800002.pdf:6.5.1.4)
+        */
+       if (set_mdrefr && scaling_up) {
+               MSC0 = new_msc0;
+               set_mdrefr_value(new_mdrefr);
+               MDCNFG = new_mdcnfg;
+               read_mdrefr = MDREFR;
+       }
+
+       CCCR = regs->cccr;
+       mainstone_set_freq(regs->clkcfg);
+
+       /* if memclk is scaling down, set MDREFR after freq change
+        * (2800002.pdf:6.5.1.4)
+        */
+       if (set_mdrefr && !scaling_up) {
+               MSC0 = new_msc0;
+               set_mdrefr_value(new_mdrefr);
+               MDCNFG = new_mdcnfg;
+               read_mdrefr = MDREFR;
+       }
+}
+
+static void mainstone_scale_voltage(struct oppoint_regs *regs)
+{
+       mainstone_set_voltage(regs->voltage);
+}
+
+static void mainstone_scale_voltage_coupled(struct oppoint_regs *regs)
+{
+       mainstone_prep_set_voltage(regs->voltage);
+}
+
+static void calculate_lcd_freq(struct md_opt *opt)
+{
+       int k = 1;              /* lcd divisor */
+
+       /* L is verified to be between PLL_L_MAX and PLL_L_MIN in */
+       if (opt->l == -1) {
+               opt->lcd = -1;
+               return;
+       }
+
+       if (opt->l > 16) {
+               /* When L=17-31, K=4 */
+               k = 4;
+       } else if (opt->l > 7) {
+               /* When L=8-16, K=2 */
+               k = 2;
+       }
+
+       /* Else, when L=2-7, K=1 */
+
+       opt->lcd = 13000 * opt->l / k;
+}
+
+static void calculate_reg_values(struct md_opt *opt)
+{
+       int f = 0;              /* frequency change bit */
+       int turbo = 0;          /* turbo mode bit; depends on N value */
+
+       opt->regs.voltage = opt->v;
+/*
+  CCCR
+    | 31| 30|29-28| 27| 26| 25|24-11| 10| 9 | 8 | 7 |6-5  | 4 | 3 | 2 | 1 | 0 |
+    | C | P |     | L | P |   |     |         |     |             |
+    | P | P |     | C | L |   |     |         |     |             |
+    | D | D |resrv| D | L | A |resrv|  2 * N   |resrv|    L          |
+    | I | I |     | 2 | . |   |     |         |     |             |
+    | S | S |     | 6 | . |   |     |         |     |             |
+
+    A: Alternate setting for MEMC clock
+       0 = MEM clock frequency as specified in YB's table 3-7
+       1 = MEM clock frq = System Bus Frequency
+
+
+  CLKCFG
+    | 31------------------------------------------- | 3 | 2  | 1 | 0 |
+    | --------------------------------------------- | B | HT | F | T |
+
+    B = Fast-Bus Mode  0: System Bus is half of run-mode
+                      1: System Bus is equal to run-mode
+                      NOTE: only allowed when L <= 16
+
+    HT = Half-Turbo    0: core frequency = run or turbo, depending on T bit
+                      1: core frequency = turbo frequency / 2
+                      NOTE: only allowed when 2N = 6 or 2N = 8
+
+    F = Frequency change
+                      0: No frequency change is performed
+                      1: Do frequency-change
+
+    T = Turbo Mode     0: CPU operates at run Frequency
+                      1: CPU operates at Turbo Frequency (when n2 > 2)
+
+*/
+       /* Set the CLKCFG with B, T, and HT */
+       if (opt->b != -1 && opt->n != -1) {
+               f = 1;
+
+               /*When N2=2, Turbo Mode equals Run Mode, so it
+                  does not really matter if this is >2 or >=2
+                */
+               if (opt->n > 2) {
+                       turbo = 0x1;
+               }
+               opt->regs.clkcfg = (opt->b << 3) + (f << 1) + turbo;
+       } else {
+               f = 0x1;
+               opt->regs.clkcfg = (f << 1);
+       }
+
+       /*
+          What about when n2=0 ... it is not defined by the yellow
+          book
+        */
+       if (opt->n != -1) {
+               /* N2 is 4 bits, L is 5 bits */
+               opt->regs.cccr = ((opt->n & 0xF) << 7) + (opt->l & 0x1F);
+       }
+
+       if (opt->cccra > 0) {
+               /* Turn on the CCCR[A] bit */
+               opt->regs.cccr |= (1 << 25);
+       }
+
+       /* 13M Mode */
+       if (opt->l == 1) {
+       }
+
+       if ( (opt->l > 1) && (opt->cpll_enabled == 0) ) {
+                printk(KERN_WARNING
+                 "DPM: internal error if l>1 CPLL must be On\n");
+       }
+       if( (opt->cpll_enabled == 1) && (opt->ppll_enabled == 0) ){
+                printk(KERN_WARNING
+                "DPM: internal error CPLL=On PPLL=Off is NOT
supported in hardware\n");
+       }
+       if(opt->cpll_enabled == 0) {
+                opt->regs.cccr |= (CCCR_CPDIS_BIT_ON);
+       }
+       if(opt->ppll_enabled == 0) {
+                opt->regs.cccr |= (CCCR_PPDIS_BIT_ON);
+       }
+
+}
+
+/* This routine computes the "forward" frequency scaler flags
+ * for moving the system
+ * from the current operating point to the new operating point.  The resulting
+ * fscaler is applied to the registers of the new operating point.
+ */
+void compute_fscaler_flags(struct md_opt *cur, struct md_opt *new)
+{
+       int current_n, ccsr;
+
+       ccsr = CCSR;
+       current_n = (ccsr & CCCR_N_MASK) >> 7;
+       fscaler_flags = FSCALER_NOP;
+       /* If new CPU is 0, that means sleep, we do NOT switch PLLs
+          if going to sleep.
+        */
+       if (!new->cpu) {
+               if (new->sleep_mode == CPUMODE_DEEPSLEEP) {
+                       fscaler_flags |= FSCALER_DEEPSLEEP;
+               } else if (new->sleep_mode == CPUMODE_STANDBY) {
+                       fscaler_flags |= FSCALER_STANDBY;
+               } else {
+                       fscaler_flags |= FSCALER_SLEEP;
+               }
+       } else {
+
+               /*
+                * If exiting 13M mode, set the flag so we can do the extra
+                * work to get out before the frequency change
+                */
+               if( ((cur->cpll_enabled == 0) && (new->cpll_enabled ==1)) ||
+                       ((cur->ppll_enabled == 0) && (new->ppll_enabled ==1)) ){
+                       fscaler_flags |= FSCALER_XPLLON;
+               }
+
+       }
+
+
+       /* if CPU is *something*, it means we are not going to sleep */
+       if ((new->cpu) &&
+           /* And something has indeed changed */
+           ((new->regs.cccr != cur->regs.cccr) ||
+            (new->regs.clkcfg != cur->regs.clkcfg))) {
+
+               /* Find out if it is *just* a turbo bit change */
+               if ((cur->l == new->l) &&
+                   (cur->cccra == new->cccra) &&
+                   (cur->b == new->b) &&
+                   (cur->half_turbo == new->half_turbo)) {
+                       /*
+                        * If the real, current N is a turbo freq and
+                        * the new N is not a turbo freq, then set
+                        * TURBO_OFF and do not change N
+                        */
+                       if ((cur->n > 1) && (new->n == 2)) {
+                               fscaler_flags |= FSCALER_TURBO_OFF;
+                       }
+                       /*
+                        * Else if the current operating point's N is
+                        * not-turbo and the new N is the desired
+                        * destination N, then set TURBO_ON
+                        */
+                       else if ((cur->n == 2) && (new->n == current_n)) {
+                               /*
+                                * Desired N must be what is current
+                                * set in the CCCR/CCSR
+                                */
+                               fscaler_flags |= FSCALER_TURBO_ON;
+                       }
+                       /* Else, fall through to regular FCS     */
+               }
+               if (!(fscaler_flags & FSCALER_TURBO)) {
+                       /* It this is not a Turbo bit only change, it
+                          must be a regular FCS
+                        */
+                       fscaler_flags |= FSCALER_CPUFREQ;
+               }
+               loops_per_jiffy = new->lpj;
+       }
+
+       if (new->half_turbo != cur->half_turbo) {
+               loops_per_jiffy = new->lpj;
+
+               if (new->half_turbo)
+                       fscaler_flags |= FSCALER_HALFTURBO_ON;
+               else
+                       fscaler_flags |= FSCALER_HALFTURBO_OFF;
+       }
+
+       if (new->regs.voltage != cur->regs.voltage)
+               fscaler_flags |= FSCALER_VOLTAGE;
+
+}
+
+static int pxa27x_transition(struct oppoint *cur, struct oppoint *new)
+{
+       int rc = 0;
+       unsigned target_v;
+       struct md_opt *md_cur, *md_new;
+
+       pr_debug("%s: %s => %s\n", __FUNCTION__, cur->name, new->name);
+
+       md_cur = (struct md_opt *)cur->md_data;
+       md_new = (struct md_opt *)new->md_data;
+
+       /* fully define the new opt, if necessary, based on values
+          from the current opt
+        */
+       mainstone_fully_define_opt(cur, new);
+       target_v = md_new->v;
+
+       /* In accordance with Yellow Book section 3.7.6.3, "Coupling
+          Voltage Change with Frequency Change", always set the
+          voltage first (setting the FVC bit in the PCFR) and then do
+          the frequency change
+        */
+       rc = mainstone_fscale(cur, new);
+       if (rc == 0)
+               current_state = new;
+
+       udelay(new->latency);
+
+       return rc;
+}
+
+static int mainstone_fscale(struct oppoint *c, struct oppoint *n)
+{
+       struct md_opt *cur = (struct md_opt *)c->md_data;
+       struct md_opt *new = (struct md_opt *)n->md_data;
+
+       compute_fscaler_flags(cur, new);
+
+       mainstone_fscaler(&new->regs);
+
+}
+
+void mainstone_fully_define_opt(struct oppoint *c, struct oppoint *n)
+{
+       struct md_opt *cur = (struct md_opt *)c->md_data;
+       struct md_opt *new = (struct md_opt *)n->md_data;
+
+       if (new->v == -1)
+               new->v = cur->v;
+       if (new->l == -1)
+               new->l = cur->l;
+       if (new->n == -1)
+               new->n = cur->n;
+       if (new->b == -1)
+               new->b = cur->b;
+       if (new->half_turbo == -1)
+               new->half_turbo = cur->half_turbo;
+       if (new->cccra == -1)
+               new->cccra = cur->cccra;
+       if (new->cpll_enabled == -1)
+               new->cpll_enabled = cur->cpll_enabled;
+       if (new->ppll_enabled == -1)
+               new->ppll_enabled = cur->ppll_enabled;
+       if (new->sleep_mode == -1)
+               new->sleep_mode = cur->sleep_mode;
+
+#ifdef CONFIG_BULVERDE_B0
+       /* for "B0"-revision PLLs have the same value */
+       new->ppll_enabled = new->cpll_enabled;
+#endif
+       /* PXA27x manual ("Yellow book") 3.5.5 (Table 3-7) states that
+        * CPLL-"On" and PPLL-"Off"
+        * configuration is forbidden (all others seem to be OK for "B0")
+        * for "C0" boards we suppose that this configuration is also enabled.
+        * PXA27x manual ("Yellow book") also states at 3.5.7.1 (page 3-25)
+        * that "CCCR[PPDIS] and CCCR[CPDIS] must always be identical and
+        * changed together". "If PLLs are to be turned off using xPDIS then
+        * set xPDIS before frequency change and clear xPDIS after frequency
+        * change"
+        */
+
+       if (new->n > 2) {
+               new->turbo = 1;
+               /* turbo mode: 13K * L * (N/2)
+                  Shift at the end to divide N by 2 for Turbo mode or
+                  by 4 for Half-Turbo mode )
+                */
+               new->cpu = (13000 * new->l * new->n) >>
+                   ((new->half_turbo == 1) ? 2 : 1);
+       } else {
+               new->turbo = 0;
+               /* run mode */
+               new->cpu = 13000 * new->l;
+       }
+       /* lcd freq is derived from L */
+       calculate_lcd_freq(new);
+       calculate_reg_values(new);
+       /* We want to keep a baseline loops_per_jiffy/cpu-freq ratio
+          to work off of for future calculations, especially when
+          emerging from sleep when there is no current cpu frequency
+          to calculate from (because cpu-freq of 0 means sleep).
+        */
+       if (!saved_loops_per_jiffy) {
+               saved_loops_per_jiffy = loops_per_jiffy;
+               saved_cpu_freq = cur->cpu;
+       }
+       if (!saved_cpu_freq) {
+               saved_cpu_freq = c->frequency;
+       }
+       /*
+        * a dedicated method for updating jiffies when frequency is changed
+        */
+       if (new->cpu) {
+               /* Normal change (not sleep), just compute. Always use
+                  the "baseline" lpj and freq */
+               new->lpj = oppoint_compute_lpj(saved_loops_per_jiffy,
+                   saved_cpu_freq, new->cpu);
+       } else {
+               /* If sleeping, keep the old LPJ */
+               new->lpj = loops_per_jiffy;
+       }
+}
+
+static void xpll_on(struct oppoint_regs *regs, int fscaler_flags)
+{
+       int tmp_cccr, tmp_ccsr;
+       int new_cpllon=0, new_pllon=0, cur_cpllon=0;
+       int  cur_pllon=0, start_cpll=0, start_pll=0;
+
+       tmp_ccsr = CCSR;
+
+       if ((regs->cccr & CCCR_CPDIS_BIT_ON) == 0)
+               new_cpllon=1;
+       if ((regs->cccr & CCCR_PPDIS_BIT_ON) == 0)
+               new_pllon=1;
+       if (((tmp_ccsr >> 31) & 0x1) == 0)
+               cur_cpllon=1;
+       if (((tmp_ccsr >> 30) & 0x1) == 0)
+               cur_pllon=1;
+
+       if ((new_cpllon == 1) && (cur_cpllon == 0)) {
+               start_cpll=1;
+       }
+       if ((new_pllon == 1) && (cur_pllon == 0)) {
+               start_pll=1;
+       }
+
+       if (!(fscaler_flags & FSCALER_XPLLON)) {
+               return;
+       }
+       if ((start_cpll == 0) && (start_pll == 0)) {
+               return;
+       }
+       /* NOTE: the Yellow Book says that exiting 13M mode requires a
+          PLL relock, which takes at least 120uS, so the book suggests
+          the OS could use a timer to keep busy until it is time to
+          check the CCSR bits which must happen before changing the
+          frequency back.
+
+          For now, we'll just loop.
+        */
+
+       /* From Yellow Book, page 3-31, section 3.5.7.5 13M Mode
+
+          Exiting 13M Mode:
+
+          1. Remain in 13M mode, but early enable the PLL via
+          CCCR[CPDIS, PPDIS]=11, and CCCR[PLL_EARLY_EN]=1. Doing
+          so will allow the PLL to be started early.
+
+          2. Read CCCR and compare to make sure that the data was
+          correctly written.
+
+          3. Check to see if CCS[CPLOCK] and CCSR[PPLOCK] bits are
+          both set. Once these bits are both high, the PLLs are
+          locked and you may move on.
+
+          4. Note that the CPU is still in 13M mode, but the PLLs are
+          started.
+
+          5. Exit from 13M mode by writing CCCR[CPDIS, PPDIS]=00, but
+          maintain CCCR[PLL_EARLY_EN]=1. This bit will be cleared
+          by the imminent frequency change.
+        */
+
+       /* Step 1 */
+       tmp_cccr = CCCR;
+       if (start_cpll)
+               tmp_cccr |= CCCR_CPDIS_BIT_ON;
+       if (start_pll)
+               tmp_cccr |= CCCR_PPDIS_BIT_ON;
+       tmp_cccr |= CCCR_PLL_EARLY_EN_BIT_ON;
+
+       CCCR = tmp_cccr;
+
+       /* Step 2 */
+       tmp_cccr = CCCR;
+
+       if ((tmp_cccr & CCCR_PLL_EARLY_EN_BIT_ON) != CCCR_PLL_EARLY_EN_BIT_ON) {
+               printk(KERN_WARNING
+                      "DPM: Warning: PLL_EARLY_EN is NOT on\n");
+       }
+       if ((start_cpll==1) &&
+             ((tmp_cccr & CCCR_CPDIS_BIT_ON) != CCCR_CPDIS_BIT_ON)) {
+               printk(KERN_WARNING
+                      "DPM: Warning: CPDIS is NOT on\n");
+       }
+       if ((start_pll==1) &&
+             (tmp_cccr & CCCR_PPDIS_BIT_ON) != CCCR_PPDIS_BIT_ON) {
+               printk(KERN_WARNING
+                      "DPM: Warning: PPDIS is NOT on\n");
+       }
+
+       /* Step 3 */
+       {
+               /* Note: the point of this is to "wait" for the lock
+                  bits to be set; the Yellow Book says this may take
+                  a while, but observation indicates that it is
+                  instantaneous
+                */
+
+               long volatile int i = 0;
+
+               int cpll_complete=1;
+               int pll_complete=1;
+               if (start_cpll==1)
+                       cpll_complete=0;
+               if (start_pll==1)
+                       pll_complete=0;
+
+               /*loop  arbitrary big value to prevent  looping forever */
+               for (i = 0; i < 999999; i++) {
+                       tmp_ccsr = CCSR;
+
+                       if ((tmp_ccsr & CCSR_CPLL_LOCKED) == CCSR_CPLL_LOCKED) {
+                               /*CPLL locked*/
+                               cpll_complete=1;
+                       }
+                       if ((tmp_ccsr & CCSR_PPLL_LOCKED) == CCSR_PPLL_LOCKED) {
+                               /*PPLL locked*/
+                               pll_complete=1;
+                       }
+                       if ((cpll_complete == 1) && (pll_complete == 1)) {
+                               break;
+                       }
+               }
+       }
+
+       /* Step 4: NOP */
+
+       /* Step 5
+          Clear the PLL disable bits - do NOT do it here.
+        */
+
+       /* But leave EARLY_EN on; it will be cleared by the frequency change */
+       regs->cccr |= CCCR_PLL_EARLY_EN_BIT_ON;
+       /* Do not set it now
+          Step 6: Now go continue on with frequency change
+          We do this step later as if voltage is too low,
+          we must ensure that it rised up  before entereng to higher
+          freq mode or simultaniously
+        */
+}
+
+static void mainstone_fscaler(struct oppoint_regs *regs)
+{
+       unsigned int cccr, clkcfg = 0;
+       unsigned long s;
+
+       /* If no flags are set, don't waste time here, just return */
+       if (fscaler_flags == FSCALER_NOP)
+               return;
+
+       if (!(fscaler_flags & FSCALER_ANY_SLEEPMODE))
+               local_irq_save(s);
+
+       /* If exiting 13M mode (turn on  PLL(s) ), do some extra work
+          before changing the CPU frequency or voltage.
+          We may turn on a combination of PLLs supported by hardware
+          only. Otherwise xpll_on(...) hang the system.
+        */
+       if (fscaler_flags & FSCALER_XPLLON)
+               xpll_on(regs, fscaler_flags);
+
+       /* if not sleeping, and have a voltage change
+          note that SLEEPMODE will handle voltage itself
+        */
+       if (((fscaler_flags & FSCALER_ANY_SLEEPMODE) == 0) &&
+           (fscaler_flags & FSCALER_VOLTAGE)) {
+               if (fscaler_flags & FSCALER_CPUFREQ) {
+                       /* coupled voltage & freq change */
+                       mainstone_scale_voltage_coupled(regs);
+               } else {
+                       /* Scale CPU voltage un-coupled with freq */
+                       mainstone_scale_voltage(regs);
+               }
+       }
+
+       if (fscaler_flags & FSCALER_CPUFREQ)    /* Scale CPU freq */
+               mainstone_scale_cpufreq(regs);
+
+       if ((fscaler_flags & FSCALER_VOLTAGE) &&
+           (fscaler_flags & FSCALER_CPUFREQ))
+               PCFR &= ~PCFR_FVC;
+
+       if (fscaler_flags & FSCALER_TURBO) {
+
+               clkcfg = mainstone_read_clkcfg();
+
+               /* Section 3.5.7 of the Yellow Book says that the F
+                  bit will be left on after a FCS, so we need to
+                  explicitly clear it. But do not change the B bit
+                */
+               clkcfg &= ~(CLKCFG_F_BIT);
+
+               if (fscaler_flags & FSCALER_TURBO_ON) {
+                       clkcfg = clkcfg | (CLKCFG_T_BIT);
+               } else {
+                       clkcfg = clkcfg & ~(CLKCFG_T_BIT);
+               }
+
+               /* enable */
+               mainstone_set_freq(clkcfg);
+       }
+
+       if ((fscaler_flags & FSCALER_HALFTURBO_ON) ||
+           (fscaler_flags & FSCALER_HALFTURBO_OFF)) {
+               if ((fscaler_flags & FSCALER_CPUFREQ) ||
+                   (fscaler_flags & FSCALER_VOLTAGE)) {
+
+                       /*
+                          From the Yellow Book, p 3-106:
+
+                          "Any two writes to CLKCFG or PWRMODE
+                          registers must be separated by siz 13-MHz
+                          cycles.  This requirement is achieved by
+                          doing the write to the CLKCFG or POWERMODE
+                          reigster, performing a read of CCCR, and
+                          then comparing the value in the CLKCFG or
+                          POWERMODE register to the written value
+                          until it matches."
+
+                          Since the setting of half turbo is a
+                          separate write to CLKCFG, we need to adhere
+                          to this requirement.
+                        */
+                       cccr = CCCR;
+                       clkcfg = mainstone_read_clkcfg();
+                       while (clkcfg != regs->clkcfg)
+                               clkcfg = mainstone_read_clkcfg();
+               }
+
+               if (clkcfg == 0)
+                       clkcfg = regs->clkcfg;
+               /* Turn off f-bit.
+
+                  According to the Yellow Book, page 3-23, "If only
+                  HT is set, F is clear, and B is not altered, then
+                  the core PLL is not stopped."
+                */
+               clkcfg = clkcfg & ~(CLKCFG_F_BIT);
+               /* set half turbo bit */
+               if (fscaler_flags & FSCALER_HALFTURBO_ON) {
+                       clkcfg = clkcfg | (CLKCFG_HT_BIT);
+               } else {
+                       clkcfg = clkcfg & ~(CLKCFG_HT_BIT);
+               }
+
+               /* enable */
+               mainstone_set_freq(clkcfg);
+       }
+
+       /* Devices only need to scale on a core frequency
+          change. Half-Turbo changes are separate from the regular
+          frequency changes, so Half-Turbo changes do not need to
+          trigger a device recalculation.
+
+          NOTE: turbo-mode-only changes could someday also be
+          optimized like Half-Turbo (to not trigger a device
+          recalc).
+        */
+
+       if (fscaler_flags & FSCALER_ANY_SLEEPMODE) {
+               /* NOTE: voltage needs i2c, so be sure to change
+                  voltage BEFORE* calling device_suspend
+                */
+
+               if (fscaler_flags & FSCALER_VOLTAGE) {
+                       /* Scale CPU voltage un-coupled with freq */
+                       mainstone_scale_voltage(regs);
+               }
+
+               if (fscaler_flags & FSCALER_SLEEP) {
+                       pm_suspend(&sleep);
+               } else if (fscaler_flags & FSCALER_STANDBY) {
+                       pm_suspend(&standby);
+               } else if (fscaler_flags & FSCALER_DEEPSLEEP) {
+                       pm_suspend(&deepsleep);
+               }
+
+               /* Here when we wake up. */
+
+       } else {
+               local_irq_restore(s);
+       }
+}
+
+/*
+ * Fully determine the current machine-dependent operating point, and fill in a
+ * structure presented by the caller.
+ */
+
+void mainstone_get_current_info(void)
+{
+       unsigned int tmp_cccr;
+       unsigned int cpdis;
+       unsigned int ppdis;
+       struct md_opt *opt = (struct md_opt *)current_state->md_data;
+
+       /* You should read CCSR to see what's up...but there is no A
+          bit in the CCSR, so we'll grab it from the CCCR.
+        */
+       tmp_cccr = CCCR;
+       opt->cccra = (tmp_cccr >> 25) & 0x1;    /* cccr[A]: bit 25 */
+
+       /* NOTE: the current voltage is not obtained, but will be left
+          as 0 in the opt which will mean no voltage change at all
+        */
+
+       opt->regs.cccr = CCSR;
+
+       opt->l = opt->regs.cccr & CCCR_L_MASK;  /* Get L */
+       opt->n = (opt->regs.cccr & CCCR_N_MASK) >> 7;   /* Get 2N */
+
+       /* This should never really be less than 2 */
+       if (opt->n < 2) {
+               opt->n = 2;
+       }
+
+       opt->regs.clkcfg = mainstone_read_clkcfg();
+       opt->b = (opt->regs.clkcfg >> 3) & 0x1; /* Fast Bus (b): bit 3 */
+       opt->turbo = opt->regs.clkcfg & 0x1;    /* Turbo is bit 1 */
+       opt->half_turbo = (opt->regs.clkcfg >> 2) & 0x1;/* HalfTurbo: bit 2 */
+
+       calculate_lcd_freq(opt);
+
+       /* are any of the PLLs is on? */
+       cpdis = ((opt->regs.cccr >> 31) & 0x1);
+       ppdis = ((opt->regs.cccr >> 30) & 0x1);
+       /*
+        * Newer revisions still require that if CPLL is On
+        * then PPLL must also be On.
+        */
+       if ((cpdis == 0) && (ppdis != 0)) {
+               /*
+                * CPLL=On PPLL=Off is NOT supported with hardware.
+                * NOTE:"B0"-revision has even more restrictive requirments
+                * to PLLs
+                */
+               printk("OpPoint: cpdis and ppdis are not in sync!\n");
+       }
+
+       opt->cpll_enabled = (cpdis == 0);
+       opt->ppll_enabled = (ppdis == 0);
+
+       /* Shift 1 to divide by 2 (because opt->n is really 2*N */
+       if (opt->turbo) {
+               opt->cpu = (13000 * opt->l * opt->n) >> 1;
+       } else {
+               /*
+                * turbo bit is off, so skip N multiplier (no matter
+                * what N really is) and use Run frequency (13K * L)
+                */
+               opt->cpu = 13000 * opt->l;
+       }
+}
+
+static void oppoint_print_opt(struct oppoint *opt)
+{
+       struct md_opt *md_opt = (struct md_opt *)opt->md_data;
+
+       printk("OpPoint : Table of defined operating points:\n");
+       printk("\t%s freq %d volt %d latency %d\n", opt->name,
+            opt->frequency, opt->voltage, opt->latency);
+
+       printk("        Name  Vol   CPU    L    N    A    B   HT  PLL
CPLL Sleep LCD\n");
+
+       printk("%12s %5d%5d%5d%5d%5d%5d%5d%5d%5d%5d%5d\n",
+           opt->name, (md_opt->v), (md_opt->cpu / 1000), md_opt->l, md_opt->n,
+           md_opt->cccra, md_opt->b, md_opt->half_turbo, md_opt->cpll_enabled,
+           md_opt->ppll_enabled, md_opt->sleep_mode, (md_opt->lcd / 1000));
+       return ;
+}
+
+/* Crystal clock: 13MHz */
+#define BASE_CLK  13000000
+
+int __init oppoint_mainstone_init(void)
+{
+       unsigned int freq;
+       unsigned long ccsr;
+       unsigned int l;
+
+       printk("Mainstone OpPoint Power Management\n");
+
+       mainstone_clk_init();
+       mainstone_vcs_init();
+        ccsr = CCSR;
+        l  = ccsr & 0x1f;
+        freq  = l * BASE_CLK;
+
+       /*
+        * supported operating point sets.
+        * 104, 208, 312
+        * 208, 312, 416, 520
+        */
+       switch (freq) {
+           case 104000000: {
+               mainstone_setup_opt(&low, 104, &mhz104);
+               oppoint_print_opt(&low);
+               mainstone_setup_opt(&medium, 208, &mhz208);
+               oppoint_print_opt(&medium);
+               mainstone_setup_opt(&high, 312, &mhz312);
+               oppoint_print_opt(&high);
+               current_state = &medium;
+               break;
+           }
+           case 208000000: {
+               mainstone_setup_opt(&low, 208, &mhz208hi);
+               oppoint_print_opt(&low);
+               mainstone_setup_opt(&medium, 312, &mhz312hi);
+               oppoint_print_opt(&medium);
+               mainstone_setup_opt(&high, 416, &mhz416hi);
+               oppoint_print_opt(&high);
+               mainstone_setup_opt(&highest, 520, &mhz520hi);
+               oppoint_print_opt(&highest);
+               break;
+
+           }
+           default: {
+               printk("OpPoint: unknown frequency set %d\n", freq);
+               break;
+           }
+       }
+
+        if (lowest.frequency)
+               register_operating_point(&lowest);
+        if (low.frequency)
+                register_operating_point(&low);
+        if (mediumlow.frequency)
+                register_operating_point(&mediumlow);
+        if (medium.frequency)
+                register_operating_point(&medium);
+        if (mediumhigh.frequency)
+                register_operating_point(&mediumhigh);
+        if (high.frequency) {
+                register_operating_point(&high);
+               current_state = &high;
+        }
+        if (highest.frequency) {
+                register_operating_point(&highest);
+               current_state = &highest;
+        }
+       /*
+        * add sleep states
+        */
+       mainstone_setup_opt(&sleep, 0, &md_sleep);
+       register_operating_point(&sleep);
+       oppoint_print_opt(&sleep);
+       mainstone_setup_opt(&deepsleep, 0, &md_deepsleep);
+       register_operating_point(&deepsleep);
+       oppoint_print_opt(&deepsleep);
+       mainstone_setup_opt(&standby, 0, &md_standby);
+       register_operating_point(&standby);
+       oppoint_print_opt(&standby);
+
+       return 0;
+}
+
+void __exit oppoint_mainstone_exit(void) {
+       mainstone_freq_cleanup();
+       mainstone_voltage_cleanup();
+}
+
+__initcall(oppoint_mainstone_init);
+__exitcall(oppoint_mainstone_exit);
Index: linux-2.6.17/arch/arm/Kconfig
===================================================================
--- linux-2.6.17.orig/arch/arm/Kconfig
+++ linux-2.6.17/arch/arm/Kconfig
@@ -690,7 +690,7 @@ config XIP_PHYS_ADDR

 endmenu

-if (ARCH_SA1100 || ARCH_INTEGRATOR || ARCH_OMAP)
+if (ARCH_SA1100 || ARCH_INTEGRATOR || ARCH_OMAP || ARCH_PXA)

 menu "CPU Frequency scaling"



David

Re: OpPoint summary

[Auke Kok]

David Singleton wrote:

> +static const struct cpu_id cpu_ids[] = {
> +       [CPU_BANIAS]    = { 6,  9, 5 },
> +       [CPU_DOTHAN_A1] = { 6, 13, 1 },
> +       [CPU_DOTHAN_A2] = { 6, 13, 2 },
> +       [CPU_DOTHAN_B0] = { 6, 13, 6 },
> +       [CPU_MP4HT_D0]  = {15,  3, 4 },
> +       [CPU_MP4HT_E0]  = {15,  4, 1 },
> +};


Any reason why { 6, 13, 8 } is missing? My lenovo T43 identifies itself as such:

processor       : 0
vendor_id       : GenuineIntel
cpu family      : 6
model           : 13
model name      : Intel(R) Pentium(R) M processor 1.86GHz
stepping        : 8

I'm not sure a Dothan B1 exists, but some postings suggest even C0 and C1 are 
valid steppings. I'm sure OpPoint could work with those as well.

Auke

Re: OpPoint summary

[Auke Kok]

David Singleton wrote:

> +static const struct cpu_id cpu_ids[] = {
> +       [CPU_BANIAS]    = { 6,  9, 5 },
> +       [CPU_DOTHAN_A1] = { 6, 13, 1 },
> +       [CPU_DOTHAN_A2] = { 6, 13, 2 },
> +       [CPU_DOTHAN_B0] = { 6, 13, 6 },
> +       [CPU_MP4HT_D0]  = {15,  3, 4 },
> +       [CPU_MP4HT_E0]  = {15,  4, 1 },
> +};


Any reason why { 6, 13, 8 } is missing? My lenovo T43 identifies itself as such:

processor       : 0
vendor_id       : GenuineIntel
cpu family      : 6
model           : 13
model name      : Intel(R) Pentium(R) M processor 1.86GHz
stepping        : 8

I'm not sure a Dothan B1 exists, but some postings suggest even C0 and C1 are 
valid steppings. I'm sure OpPoint could work with those as well.

Auke

Re: [linux-pm] OpPoint summary

[Vitaly Wool]

On 9/14/06, Auke Kok <auke-jan.h.kok@intel.com> wrote:
> David Singleton wrote:
>
> > +static const struct cpu_id cpu_ids[] = {
> > +       [CPU_BANIAS]    = { 6,  9, 5 },
> > +       [CPU_DOTHAN_A1] = { 6, 13, 1 },
> > +       [CPU_DOTHAN_A2] = { 6, 13, 2 },
> > +       [CPU_DOTHAN_B0] = { 6, 13, 6 },
> > +       [CPU_MP4HT_D0]  = {15,  3, 4 },
> > +       [CPU_MP4HT_E0]  = {15,  4, 1 },
> > +};
>
>
> Any reason why { 6, 13, 8 } is missing? My lenovo T43 identifies itself as such:
>
> processor       : 0
> vendor_id       : GenuineIntel
> cpu family      : 6
> model           : 13
> model name      : Intel(R) Pentium(R) M processor 1.86GHz
> stepping        : 8
>
> I'm not sure a Dothan B1 exists, but some postings suggest even C0 and C1 are
> valid steppings. I'm sure OpPoint could work with those as well.

Heh, that shows pretty much that the approach itself is not good...
And this is only beginning.

Vitaly

Re: OpPoint summary

[David Singleton]

On 9/14/06, Auke Kok <auke-jan.h.kok@intel.com> wrote:
> David Singleton wrote:
>
> > +static const struct cpu_id cpu_ids[] = {
> > +       [CPU_BANIAS]    = { 6,  9, 5 },
> > +       [CPU_DOTHAN_A1] = { 6, 13, 1 },
> > +       [CPU_DOTHAN_A2] = { 6, 13, 2 },
> > +       [CPU_DOTHAN_B0] = { 6, 13, 6 },
> > +       [CPU_MP4HT_D0]  = {15,  3, 4 },
> > +       [CPU_MP4HT_E0]  = {15,  4, 1 },
> > +};
>
>
> Any reason why { 6, 13, 8 } is missing? My lenovo T43 identifies itself as such:
>
> processor       : 0
> vendor_id       : GenuineIntel
> cpu family      : 6
> model           : 13
> model name      : Intel(R) Pentium(R) M processor 1.86GHz
> stepping        : 8
>
> I'm not sure a Dothan B1 exists, but some postings suggest even C0 and C1 are
> valid steppings. I'm sure OpPoint could work with those as well.

Yes it could.  The centrino was the first platform I tested on and I used the
existing speedstep-centrino code from cpufreq.  The 1.86Ghz  was not in
the cpufreq base.    But you can see how easy it is to add new operating points
for a new cpu.

Adding new platform support is quite straight forward.  It basically requires
a function to transition to the new operating point and the parameters needed
for the transition.

David
>
> Auke
>

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Jon Loeliger]

On Thu, 2006-09-14 at 08:03, Pavel Machek wrote:

> Actually, laptops and zauruses seem to be the only "interesting"
> machines from pm perspective.

Well, and future parts and machines that are in the works.

>  Then there are Motorola cellphones, but
> Motorola tried hard not to enable users changing kernel... so they are
> irrelevant.
> 								Pavel

That might be a bit unfair.  Those engineers at Motorola
who put linux on the cellphones and mobile devices do
need to have the PM support.  They are NOT irrelevant.

jdl

Re: OpPoint summary

[David Singleton]

Pavel and Greg,

I've incorporated Pavels suggestions and only put suspend states
in the /sys/power/state file.  The control file for frequency and
voltage operating
point transitions is now in /sys/power/operating_points/current_point.

The /sys/power/operating_points dirctory still contains the operating
points themselves, with a frequency, voltage and latency file
for each operating point.

The oppointd power manager has been changed to use the
new control file for operating points.  It has been tested on
a centrino laptop, the 4 way Xeon server and the arm-pxa27x.

I finally got SMP tested on a 4 way Xeon server.  The patch
that supports SMP Xeon's is the oppoint-x86-p4.patch in the series.

The only files in the core framework patch now are:

        kernel/power/main.c
        include/linux/pm.h
        kernel/power/power.h

The full patch set is at

        http://source.mvista.com/~dsingleton/2.6.18-rc7

The power manager source and patch is at:

        http://source.mvista.com/~dsingleton/oppointd-1.2.3

Attached is the oppoint-core.patch.

David

Signed-Off-by: David Singleton <dsingleton@mvista.com>

 include/linux/pm.h   |   30 +++-
 kernel/power/main.c  |  361 +++++++++++++++++++++++++++++++++++++++++++++------
 kernel/power/power.h |    2
 3 files changed, 350 insertions(+), 43 deletions(-)

Index: linux-2.6.17/kernel/power/main.c
===================================================================
--- linux-2.6.17.orig/kernel/power/main.c
+++ linux-2.6.17/kernel/power/main.c
@@ -16,6 +16,7 @@
 #include <linux/init.h>
 #include <linux/pm.h>
 #include <linux/console.h>
+#include <linux/module.h>

 #include "power.h"

@@ -49,7 +50,7 @@ void pm_set_ops(struct pm_ops * ops)
  *     the platform can enter the requested state.
  */

-static int suspend_prepare(suspend_state_t state)
+static int suspend_prepare(struct oppoint * state)
 {
        int error = 0;
        unsigned int free_pages;
@@ -82,7 +83,7 @@ static int suspend_prepare(suspend_state
        }

        if (pm_ops->prepare) {
-               if ((error = pm_ops->prepare(state)))
+               if ((error = pm_ops->prepare(state->type)))
                        goto Thaw;
        }

@@ -94,7 +95,7 @@ static int suspend_prepare(suspend_state
        return 0;
  Finish:
        if (pm_ops->finish)
-               pm_ops->finish(state);
+               pm_ops->finish(state->type);
  Thaw:
        thaw_processes();
  Enable_cpu:
@@ -104,7 +105,7 @@ static int suspend_prepare(suspend_state
 }


-int suspend_enter(suspend_state_t state)
+int suspend_enter(struct oppoint * state)
 {
        int error = 0;
        unsigned long flags;
@@ -115,7 +116,7 @@ int suspend_enter(suspend_state_t state)
                printk(KERN_ERR "Some devices failed to power down\n");
                goto Done;
        }
-       error = pm_ops->enter(state);
+       error = pm_ops->enter(state->type);
        device_power_up();
  Done:
        local_irq_restore(flags);
@@ -131,36 +132,82 @@ int suspend_enter(suspend_state_t state)
  *     console that we've allocated. This is not called for suspend-to-disk.
  */

-static void suspend_finish(suspend_state_t state)
+static void suspend_finish(struct oppoint * state)
 {
        device_resume();
        resume_console();
        thaw_processes();
        enable_nonboot_cpus();
        if (pm_ops && pm_ops->finish)
-               pm_ops->finish(state);
+               pm_ops->finish(state->type);
        pm_restore_console();
 }

+struct list_head pm_list;
+static struct oppoint standby = {
+       .name = "standby",
+       .type = PM_SUSPEND_STANDBY,
+};

+static struct oppoint mem = {
+       .name = "mem",
+       .type = PM_SUSPEND_MEM,
+       .frequency = 0,
+       .voltage = 0,
+       .latency = 150,
+};

-
-static const char * const pm_states[PM_SUSPEND_MAX] = {
-       [PM_SUSPEND_STANDBY]    = "standby",
-       [PM_SUSPEND_MEM]        = "mem",
 #ifdef CONFIG_SOFTWARE_SUSPEND
-       [PM_SUSPEND_DISK]       = "disk",
+struct oppoint disk = {
+       .name = "disk",
+       .type = PM_SUSPEND_DISK,
+};
 #endif
+
+struct oppoint pm_states = {
+       .name = "default",
+       .type = PM_FREQ_CHANGE,
 };
+struct oppoint *current_state;
+
+/*
+ *
+ */
+static int pm_change_state(struct oppoint *state)
+{
+       int error = 0;
+
+       printk("OpPoint: changing from %s to %s\n", current_state->name,
+            state->name);
+       /*
+        * compare to current operating point.
+        * if different change to new operating point.
+        */
+       if (current_state == state)
+               goto out;
+
+       if ((error = state->prepare_transition(current_state, state)))
+               goto out;
+
+       if ((error = state->transition(current_state, state)))
+                state = current_state;
+
+       if ((error = state->finish_transition(current_state, state)) == 0)
+               current_state = state;
+
+out:
+       printk("OpPoint: State change returned %d\n", error);
+       return error;
+}

-static inline int valid_state(suspend_state_t state)
+static inline int valid_state(struct oppoint * state)
 {
        /* Suspend-to-disk does not really need low-level support.
         * It can work with reboot if needed. */
-       if (state == PM_SUSPEND_DISK)
+       if (state->type == PM_SUSPEND_DISK)
                return 1;

-       if (pm_ops && pm_ops->valid && !pm_ops->valid(state))
+       if (pm_ops && pm_ops->valid && !pm_ops->valid(state->type))
                return 0;
        return 1;
 }
@@ -168,7 +215,7 @@ static inline int valid_state(suspend_st

 /**
  *     enter_state - Do common work of entering low-power state.
- *     @state:         pm_state structure for state we're entering.
+ *     @state:         oppoint structure for state we're entering.
  *
  *     Make sure we're the only ones trying to enter a sleep state. Fail
  *     if someone has beat us to it, since we don't want anything weird to
@@ -177,7 +224,7 @@ static inline int valid_state(suspend_st
  *     we've woken up).
  */

-static int enter_state(suspend_state_t state)
+static int enter_state(struct oppoint *state)
 {
        int error;

@@ -186,16 +233,21 @@ static int enter_state(suspend_state_t s
        if (down_trylock(&pm_sem))
                return -EBUSY;

-       if (state == PM_SUSPEND_DISK) {
+       if (state->type == PM_SUSPEND_DISK) {
                error = pm_suspend_disk();
                goto Unlock;
        }

-       pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
+       if (state->type == PM_FREQ_CHANGE || state->type == PM_VOLT_CHANGE) {
+               error = pm_change_state(state);
+               goto Unlock;
+       }
+
+       pr_debug("PM: Preparing system for %s sleep\n", state->name);
        if ((error = suspend_prepare(state)))
                goto Unlock;

-       pr_debug("PM: Entering %s sleep\n", pm_states[state]);
+       pr_debug("PM: Entering %s sleep\n", state->name);
        error = suspend_enter(state);

        pr_debug("PM: Finishing wakeup.\n");
@@ -211,7 +263,15 @@ static int enter_state(suspend_state_t s
  */
 int software_suspend(void)
 {
-       return enter_state(PM_SUSPEND_DISK);
+       struct oppoint *this, *next;
+       struct list_head *head = &mem.list;
+       int error = 0;
+
+       list_for_each_entry_safe(this, next, head, list) {
+               if (this->type == PM_SUSPEND_DISK)
+                       error= enter_state(this);
+       }
+       return error;
 }


@@ -223,9 +283,9 @@ int software_suspend(void)
  *     structure, and enter (above).
  */

-int pm_suspend(suspend_state_t state)
+int pm_suspend(struct oppoint * state)
 {
-       if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
+       if (state->type > PM_SUSPEND_ON && state->type <= PM_SUSPEND_MAX)
                return enter_state(state);
        return -EINVAL;
 }
@@ -248,36 +308,35 @@ decl_subsys(power,NULL,NULL);

 static ssize_t state_show(struct subsystem * subsys, char * buf)
 {
-       int i;
-       char * s = buf;
+       struct oppoint *this, *next;
+       struct list_head *head = &pm_list;
+       char *s = buf;
+
+       list_for_each_entry_safe(this, next, head, list)
+               s += sprintf(s,"%s ", this->name);

-       for (i = 0; i < PM_SUSPEND_MAX; i++) {
-               if (pm_states[i] && valid_state(i))
-                       s += sprintf(s,"%s ", pm_states[i]);
-       }
        s += sprintf(s,"\n");
+
        return (s - buf);
 }

 static ssize_t state_store(struct subsystem * subsys, const char *
buf, size_t n)
 {
-       suspend_state_t state = PM_SUSPEND_STANDBY;
-       const char * const *s;
+       struct oppoint *this, *next;
+       struct list_head *head = &mem.list;
        char *p;
-       int error;
+       int error = -EINVAL;
        int len;

        p = memchr(buf, '\n', n);
        len = p ? p - buf : n;
-
-       for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
-               if (*s && !strncmp(buf, *s, len))
+       list_for_each_entry_safe(this, next, head, list) {
+               if ((strlen(this->name) == len) &&
+                  (!strncmp(this->name, buf, len))) {
+                       error = enter_state(this);
                        break;
+               }
        }
-       if (state < PM_SUSPEND_MAX && *s)
-               error = enter_state(state);
-       else
-               error = -EINVAL;
        return error ? error : n;
 }

@@ -292,12 +351,234 @@ static struct attribute_group attr_group
        .attrs = g,
 };

+static struct kobject oppoint_kobj = {
+        .kset = &power_subsys.kset,
+};
+
+struct oppoint_attribute {
+        struct attribute        attr;
+        ssize_t (*show)(struct kobject * kobj, char * buf);
+        ssize_t (*store)(struct kobject * kobj, const char * buf,
size_t count);
+};
+
+#define to_oppoint(obj) container_of(obj,struct oppoint,kobj)
+#define to_oppoint_attr(_attr) container_of(_attr,struct
oppoint_attribute,attr)
+/*
+ * the frequency, voltage and latency files are readonly
+ */
+
+static ssize_t oppoint_voltage_show(struct kobject * kobj, char * buf)
+{
+       ssize_t len;
+       struct oppoint *opt = to_oppoint(kobj);
+
+       len = sprintf(buf, "%8d\n", opt->voltage);
+
+       return len;
+}
+
+static ssize_t oppoint_voltage_store(struct kobject * kobj, const char * buf,
+       size_t n)
+{
+        return -EINVAL;
+
+}
+
+static ssize_t oppoint_frequency_show(struct kobject * kobj, char * buf)
+{
+       ssize_t len;
+       struct oppoint *opt = to_oppoint(kobj);
+
+       len = sprintf(buf, "%8d\n", opt->frequency);
+
+       return len;
+}
+
+static ssize_t oppoint_frequency_store(struct kobject * kobj,
+        const char * buf, size_t n)
+{
+        return -EINVAL;
+
+}
+
+static ssize_t oppoint_point_show(struct kobject * kobj, char * buf)
+{
+       ssize_t len;
+
+       len = sprintf(buf, "%s\n", current_state->name);
+
+       return len;
+}
+
+static ssize_t oppoint_point_store(struct kobject * kobj, const char * buf,
+       size_t n)
+{
+        struct oppoint *this, *next;
+        struct list_head *head = &pm_states.list;
+        char *p;
+        int error = -EINVAL;
+        int len;
+
+        p = memchr(buf, '\n', n);
+        len = p ? p - buf : n;
+        list_for_each_entry_safe(this, next, head, list) {
+                if ((strlen(this->name) == len) &&
+                   (!strncmp(this->name, buf, len))) {
+                        error = enter_state(this);
+                        break;
+                }
+        }
+        return error ? error : n;
+}
+
+static ssize_t oppoint_latency_show(struct kobject * kobj, char * buf)
+{
+       ssize_t len;
+       struct oppoint *opt = to_oppoint(kobj);
+
+       len = sprintf(buf, "%8d\n", opt->latency);
+
+       return len;
+}
+
+static ssize_t oppoint_latency_store(struct kobject * kobj,
+        const char * buf, size_t n)
+{
+        return -EINVAL;
+
+}
+
+static struct oppoint_attribute point_attr = {
+        .attr   = {
+                .name = "current_point",
+                .mode = 0600,
+        },
+        .show   = oppoint_point_show,
+        .store  = oppoint_point_store,
+};
+
+static struct oppoint_attribute frequency_attr = {
+        .attr   = {
+                .name = "frequency",
+                .mode = 0400,
+        },
+        .show   = oppoint_frequency_show,
+        .store  = oppoint_frequency_store,
+};
+
+static struct oppoint_attribute voltage_attr = {
+        .attr   = {
+                .name = "voltage",
+                .mode = 0400,
+        },
+        .show   = oppoint_voltage_show,
+        .store  = oppoint_voltage_store,
+};
+
+static struct oppoint_attribute latency_attr = {
+        .attr   = {
+                .name = "latency",
+                .mode = 0400,
+        },
+        .show   = oppoint_latency_show,
+        .store  = oppoint_latency_store,
+};
+
+static ssize_t
+oppoint_attr_show(struct kobject * kobj, struct attribute * attr, char * buf)
+{
+       struct oppoint_attribute * opt_attr = to_oppoint_attr(attr);
+       ssize_t ret = 0;
+
+       if (opt_attr->show)
+               ret = opt_attr->show(kobj,buf);
+       return ret;
+}
+
+static ssize_t
+oppoint_attr_store(struct kobject * kobj, struct attribute * attr,
+             const char * buf, size_t count)
+{
+       return -EINVAL;
+}
+
+static void oppoint_kobj_release(struct kobject *kobj)
+{
+       return;
+}
+
+static struct sysfs_ops oppoint_sysfs_ops = {
+       .show   = oppoint_attr_show,
+       .store  = oppoint_attr_store,
+};
+
+static struct attribute * oppoint_default_attrs[] = {
+       &frequency_attr.attr,
+       &voltage_attr.attr,
+       &latency_attr.attr,
+       NULL,
+};
+
+static struct kobj_type ktype_operating_point = {
+        .release        = oppoint_kobj_release,
+        .sysfs_ops      = &oppoint_sysfs_ops,
+        .default_attrs  = oppoint_default_attrs,
+};
+
+int unregister_operating_point(struct oppoint *opt)
+{
+       down(&pm_sem);
+       list_del_init(&opt->list);
+       sysfs_remove_file(&opt->kobj, &frequency_attr.attr);
+       sysfs_remove_file(&opt->kobj, &voltage_attr.attr);
+       sysfs_remove_file(&opt->kobj, &latency_attr.attr);
+       up(&pm_sem);
+
+       return 0;
+}
+EXPORT_SYMBOL(unregister_operating_point);
+
+int register_operating_point(struct oppoint *opt)
+{
+       down(&pm_sem);
+       kobject_set_name(&opt->kobj, opt->name);
+       opt->kobj.kset = &power_subsys.kset;
+       opt->kobj.parent = &oppoint_kobj;
+       opt->kobj.ktype = &ktype_operating_point;
+       kobject_register(&opt->kobj);
+
+       sysfs_create_file(&opt->kobj, &frequency_attr.attr);
+       sysfs_create_file(&opt->kobj, &voltage_attr.attr);
+       sysfs_create_file(&opt->kobj, &latency_attr.attr);
+
+       list_add_tail(&opt->list, &pm_states.list);
+       up(&pm_sem);
+       return 0;
+}
+EXPORT_SYMBOL(register_operating_point);

 static int __init pm_init(void)
 {
+
        int error = subsystem_register(&power_subsys);
-       if (!error)
+       if (!error) {
                error = sysfs_create_group(&power_subsys.kset.kobj,&attr_group);
+               kobject_set_name(&oppoint_kobj, "operating_points");
+               kobject_register(&oppoint_kobj);
+               sysfs_create_file(&oppoint_kobj, &point_attr.attr);
+       }
+
+
+       INIT_LIST_HEAD(&pm_states.list);
+       INIT_LIST_HEAD(&pm_list);
+
+#ifdef CONFIG_SOFTWARE_SUSPEND
+       list_add(&disk.list, &pm_list);
+#endif
+       list_add(&standby.list, &pm_list);
+       list_add(&mem.list, &pm_list);
+       current_state = &pm_states;
+
        return error;
 }

Index: linux-2.6.17/include/linux/pm.h
===================================================================
--- linux-2.6.17.orig/include/linux/pm.h
+++ linux-2.6.17/include/linux/pm.h
@@ -24,6 +24,7 @@
 #ifdef __KERNEL__

 #include <linux/list.h>
+#include <linux/kobject.h>
 #include <asm/atomic.h>

 /*
@@ -108,7 +109,32 @@ typedef int __bitwise suspend_state_t;
 #define PM_SUSPEND_STANDBY     ((__force suspend_state_t) 1)
 #define PM_SUSPEND_MEM         ((__force suspend_state_t) 3)
 #define PM_SUSPEND_DISK                ((__force suspend_state_t) 4)
-#define PM_SUSPEND_MAX         ((__force suspend_state_t) 5)
+#define PM_FREQ_CHANGE         ((__force suspend_state_t) 5)
+#define PM_VOLT_CHANGE         ((__force suspend_state_t) 6)
+#define PM_SUSPEND_MAX         ((__force suspend_state_t) 7)
+
+struct oppoint {
+       struct list_head list;
+       suspend_state_t type;
+       char *name;
+       unsigned int flags;
+       unsigned int frequency;         /* in KHz */
+       unsigned int voltage;           /* mV */
+       unsigned int latency;           /* transition latency in us */
+       int     (*prepare_transition)(struct oppoint *cur, struct oppoint *new);
+       int     (*transition)(struct oppoint *cur, struct oppoint *new);
+       int     (*finish_transition)(struct oppoint *cur, struct oppoint *new);
+
+       void *md_data;                  /* arch dependent data */
+       struct kobject kobj;
+};
+
+
+extern struct oppoint pm_states;
+extern struct oppoint *current_state;
+extern int register_operating_point(struct oppoint *opt);
+extern int unregister_operating_point(struct oppoint *opt);
+struct notifier_block;

 typedef int __bitwise suspend_disk_method_t;

@@ -128,7 +154,7 @@ struct pm_ops {

 extern void pm_set_ops(struct pm_ops *);
 extern struct pm_ops *pm_ops;
-extern int pm_suspend(suspend_state_t state);
+extern int pm_suspend(struct oppoint *state);


 /*
Index: linux-2.6.17/kernel/power/power.h
===================================================================
--- linux-2.6.17.orig/kernel/power/power.h
+++ linux-2.6.17/kernel/power/power.h
@@ -113,4 +113,4 @@ extern int swsusp_resume(void);
 extern int swsusp_read(void);
 extern int swsusp_write(void);
 extern void swsusp_close(void);
-extern int suspend_enter(suspend_state_t state);
+extern int suspend_enter(struct oppoint * state);

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Amit Kucheria]

On Thu, 2006-09-14 at 15:20 +0200, ext Pavel Machek wrote:
> Hi!
> 
> > >> from aside, it looks like you're choosing 'rules' and assign then
> > >> 'priorities' in a too arbitrary way which is by a strange accident
> > >> fits your point of view best of all.
> > >> May I remind you that Linux world is not only laptops and Sharp Zaurus? 
> > >;)
> > >
> > >Actually, laptops and zauruses seem to be the only "interesting"
> > >machines from pm perspective. Then there are Motorola cellphones, but
> > >Motorola tried hard not to enable users changing kernel... so they are
> > >irrelevant.
> > 
> > Well, I never said Zaurus was no good :)
> > Please don't forget about Nokia 770 and its possible follow-ups.
> 
> Well, for now, Nokia 770 is zaurus with wifi but without keyboard
> (mostly). It seems to be very similar to zaurus pm-wise.

You have conveniently chosen to forget that Nokia 770 does not support
suspend-to-disk - it is a S-T-R device. In fact, personally I agree with
Linus' comments elsewhere about S-T-D being irrelevant.

Regards,
Amit

-- 
Amit Kucheria <amit.kucheria@nokia.com>
Nokia

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Pavel Machek]

Hi!

> > > May I remind you that Linux world is not only laptops and Sharp Zaurus? ;)
> >
> > Actually, laptops and zauruses seem to be the only "interesting"
> > machines from pm perspective. Then there are Motorola cellphones, but
> > Motorola tried hard not to enable users changing kernel... so they are
> > irrelevant.
> 
> Get yourself some OMAP hardware then; your blinders are way too effective!
> 
> OMAP1 hardware is easily had; an OSK, or a Nokia N770.  The latter is
> battery powered already, without the hardware mods...

Well, I already have zaurus, and nokia 770 is inferior AFAICT. So the
next one will be linux cellphone...

(And IIRC zaurus lasts longer on batteries than 770 does... or at
least comparable. Maybe OMAP is more complex, but is it actually good
thing?)
								Pavel

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: cpufreq user<->kernel interface removal [was Re: community PM requirements/issues and PowerOP]

[Pavel Machek]

hi!

> Power-OP: Matt, Eugeny, Igor, myself to a much lesser extent
> Oppoint: David
> 
> Interested parties to getting operating point concepts into the main
> line kernel are CELF and MLI members.

Thanks.

> > Or, can each of the different projects send a _short_, 1 paragraph, 4
> > sentance maximum summary of the different things.  Think of it as your
> > "elevator pitch".  The different multi-page summaries ware making my
> > eyes glaze over...
> 
> CE and embedded Linux users have not been able to use cpufreq, mostly
> because those platforms don't have ACPI like FW for controlling all
> > the

?? zaurus uses cpufreq just fine, and you could do that on omap. You'd
not have powersavings coming out of powering down devices, but
otherwise it should be doable.

								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Pavel Machek]

On Thu 2006-09-14 14:25:32, Jon Loeliger wrote:
> On Thu, 2006-09-14 at 08:03, Pavel Machek wrote:
> 
> > Actually, laptops and zauruses seem to be the only "interesting"
> > machines from pm perspective.
> 
> Well, and future parts and machines that are in the works.
> 
> >  Then there are Motorola cellphones, but
> > Motorola tried hard not to enable users changing kernel... so they are
> > irrelevant.
> 
> That might be a bit unfair.  Those engineers at Motorola
> who put linux on the cellphones and mobile devices do
> need to have the PM support.  They are NOT irrelevant.

Of course I am unfair. It is nice that motorola ships linux-based
cellphones, but they made really sure that users can't hack
them... which is considered anti-social by the community. 

So it would be nice if kernel matched requirements by Motorola, but it
is *way* more important that it matches requirements by Sharp and
notebook requirements... because Sharp & notebook manufacturers
actually play fair.
								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: OpPoint summary

[Pavel Machek]

Hi!

> I've incorporated Pavels suggestions and only put suspend states
> in the /sys/power/state file.  The control file for frequency and

Ok...

> voltage operating
> point transitions is now in
> /sys/power/operating_points/current_point.

How do you handle SMP? If I want full speed on CPU0 and 100MHz on cpu
1?
> --- linux-2.6.17.orig/kernel/power/main.c
> +++ linux-2.6.17/kernel/power/main.c
> @@ -16,6 +16,7 @@
> #include <linux/init.h>
> #include <linux/pm.h>
> #include <linux/console.h>
> +#include <linux/module.h>
> 
> #include "power.h"
> 
> @@ -49,7 +50,7 @@ void pm_set_ops(struct pm_ops * ops)
>  *     the platform can enter the requested state.
>  */
> 
> -static int suspend_prepare(suspend_state_t state)
> +static int suspend_prepare(struct oppoint * state)

...so why this change?
									Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: OpPoint summary

[Pavel Machek]

On Sat 2006-09-16 22:07:15, David Singleton wrote:
> Pavel and Greg,
> 
> I've incorporated Pavels suggestions and only put suspend states
> in the /sys/power/state file.  The control file for frequency and
> voltage operating
> point transitions is now in
> /sys/power/operating_points/current_point.

Ouch and it still needs description of your proposed user<->kernel
interface, explanation why it is good thing (I do not thing it is),
and probably explanation why you are competing with powerOP framework,
rather than working with them.
								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Vitaly Wool]

On 9/17/06, Pavel Machek <pavel@ucw.cz> wrote:
> (And IIRC zaurus lasts longer on batteries than 770 does... or at
> least comparable. Maybe OMAP is more complex, but is it actually good
> thing?)

Well, it might as well depend on the batteries' volume :)
Also, WiFi needs more power.

Vitaly

Re: cpufreq user<->kernel interface removal [was Re: community PM requirements/issues and PowerOP]

[Vitaly Wool]

Pavel,

On 9/17/06, Pavel Machek <pavel@ucw.cz> wrote:
> ?? zaurus uses cpufreq just fine, and you could do that on omap. You'd
> not have powersavings coming out of powering down devices, but
> otherwise it should be doable.

I do think you'd better broaden your views here ;)
cpufreq as it is is not well-suitable for complex power management
cases where you need to switch between multiple oscillators/clock
sources/PLLs etc to gain the most efficien power management.
Zaurus is not that complicated in PM AFAIK and I'm sure it could be
even better if it used PowerOP or similar solution. :)

Vitaly

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Pavel Machek]

Hi!

> > > >> from aside, it looks like you're choosing 'rules' and assign then
> > > >> 'priorities' in a too arbitrary way which is by a strange accident
> > > >> fits your point of view best of all.
> > > >> May I remind you that Linux world is not only laptops and Sharp Zaurus? 
> > > >;)
> > > >
> > > >Actually, laptops and zauruses seem to be the only "interesting"
> > > >machines from pm perspective. Then there are Motorola cellphones, but
> > > >Motorola tried hard not to enable users changing kernel... so they are
> > > >irrelevant.
> > > 
> > > Well, I never said Zaurus was no good :)
> > > Please don't forget about Nokia 770 and its possible follow-ups.
> > 
> > Well, for now, Nokia 770 is zaurus with wifi but without keyboard
> > (mostly). It seems to be very similar to zaurus pm-wise.
> 
> You have conveniently chosen to forget that Nokia 770 does not support
> suspend-to-disk - it is a S-T-R device. In fact, personally I agree with
> Linus' comments elsewhere about S-T-D being irrelevant.

Now I do not understand... this was power savings debate, no? Zaurus
basically does not support S-T-D either (or at least I do not use it
there), and I agree that S-T-D is irrelevant in the long term. And it
is hardly relevant for non-PC machines _now_.

								Pavel


-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: cpufreq user<->kernel interface removal [was Re: community PM requirements/issues and PowerOP]

[Pavel Machek]

On Sun 2006-09-17 17:10:36, Vitaly Wool wrote:
> Pavel,
> 
> On 9/17/06, Pavel Machek <pavel@ucw.cz> wrote:
> >?? zaurus uses cpufreq just fine, and you could do that on omap. You'd
> >not have powersavings coming out of powering down devices, but
> >otherwise it should be doable.
> 
> I do think you'd better broaden your views here ;)
> cpufreq as it is is not well-suitable for complex power management
> cases where you need to switch between multiple oscillators/clock
> sources/PLLs etc to gain the most efficien power management.
> Zaurus is not that complicated in PM AFAIK and I'm sure it could be
> even better if it used PowerOP or similar solution. :)

Well, I do think you'd better broaden your views here ;)
Solutions you propose are not well-suitable for big systems, like 8
cpu server box with 40 PCI devices.

What we need to do is something that works well from whole range, from
770 through thinkpad x60 to 8x Xeon server.
								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Amit Kucheria]

On Sun, 2006-09-17 at 15:18 +0200, ext Pavel Machek wrote:
>  
> > > Well, for now, Nokia 770 is zaurus with wifi but without keyboard
> > > (mostly). It seems to be very similar to zaurus pm-wise.
> > 
> > You have conveniently chosen to forget that Nokia 770 does not support
> > suspend-to-disk - it is a S-T-R device. In fact, personally I agree with
> > Linus' comments elsewhere about S-T-D being irrelevant.
> 
> Now I do not understand... this was power savings debate, no? Zaurus
> basically does not support S-T-D either (or at least I do not use it
> there), and I agree that S-T-D is irrelevant in the long term. And it
> is hardly relevant for non-PC machines _now_.
> 
> 								Pavel

I was referring to the default method of power save on Zaurus on the
Sharp ROMs. It was S-T-D (Flash), IIRC. I do not recall drivers doing
runtime power management on Zaurus; that is a major difference from
Nokia 770.

Regards,
Amit
-- 
Amit Kucheria <amit.kucheria@nokia.com>
Nokia

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Pavel Machek]

On Sun 2006-09-17 16:28:23, Amit Kucheria wrote:
> On Sun, 2006-09-17 at 15:18 +0200, ext Pavel Machek wrote:
> >  
> > > > Well, for now, Nokia 770 is zaurus with wifi but without keyboard
> > > > (mostly). It seems to be very similar to zaurus pm-wise.
> > > 
> > > You have conveniently chosen to forget that Nokia 770 does not support
> > > suspend-to-disk - it is a S-T-R device. In fact, personally I agree with
> > > Linus' comments elsewhere about S-T-D being irrelevant.
> > 
> > Now I do not understand... this was power savings debate, no? Zaurus
> > basically does not support S-T-D either (or at least I do not use it
> > there), and I agree that S-T-D is irrelevant in the long term. And it
> > is hardly relevant for non-PC machines _now_.
> 
> I was referring to the default method of power save on Zaurus on the
> Sharp ROMs. It was S-T-D (Flash), IIRC. I do not recall drivers doing
> runtime power management on Zaurus; that is a major difference from
> Nokia 770.

I'm pretty sure Zauruses do s-t-ram. Flash is read only during normal
operation.

I'm very sure Sharp zaurus sl-5500 does s-t-ram. After all, it has
16MB of flash and 64MB of ram. Suspend-to-flash is not an option.

								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Amit Kucheria]

(Modified recipient list)

On Sun, 2006-09-17 at 15:40 +0200, ext Pavel Machek wrote:
> On Sun 2006-09-17 16:28:23, Amit Kucheria wrote:
> > On Sun, 2006-09-17 at 15:18 +0200, ext Pavel Machek wrote:
> > >  
> > > > > Well, for now, Nokia 770 is zaurus with wifi but without keyboard
> > > > > (mostly). It seems to be very similar to zaurus pm-wise.
> > > > 
> > > > You have conveniently chosen to forget that Nokia 770 does not support
> > > > suspend-to-disk - it is a S-T-R device. In fact, personally I agree with
> > > > Linus' comments elsewhere about S-T-D being irrelevant.
> > > 
> > > Now I do not understand... this was power savings debate, no? Zaurus
> > > basically does not support S-T-D either (or at least I do not use it
> > > there), and I agree that S-T-D is irrelevant in the long term. And it
> > > is hardly relevant for non-PC machines _now_.
> > 
> > I was referring to the default method of power save on Zaurus on the
> > Sharp ROMs. It was S-T-D (Flash), IIRC. I do not recall drivers doing
> > runtime power management on Zaurus; that is a major difference from
> > Nokia 770.
> 
> I'm pretty sure Zauruses do s-t-ram. Flash is read only during normal
> operation.
> 
> I'm very sure Sharp zaurus sl-5500 does s-t-ram. After all, it has
> 16MB of flash and 64MB of ram. Suspend-to-flash is not an option.
> 
> 								Pavel

If that is the case, I stand corrected. Did the drivers support dynamic
idling?

Although something about the time it took to resume still bothers me....
I will try to find time to flash it and check.


-- 
Amit Kucheria <amit.kucheria@nokia.com>
Nokia

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Preece Scott-PREECE]

> From: Pavel Machek [mailto:pavel@ucw.cz] 
> 
> On Thu 2006-09-14 14:25:32, Jon Loeliger wrote:
> > On Thu, 2006-09-14 at 08:03, Pavel Machek wrote:
> > 
> > > Actually, laptops and zauruses seem to be the only "interesting"
> > > machines from pm perspective.
> > 
> > Well, and future parts and machines that are in the works.
> > 
> > >  Then there are Motorola cellphones, but Motorola tried 
> hard not to 
> > > enable users changing kernel... so they are irrelevant.
> > 
> > That might be a bit unfair.  Those engineers at Motorola 
> who put linux 
> > on the cellphones and mobile devices do need to have the PM 
> support.  
> > They are NOT irrelevant.
> 
> Of course I am unfair. It is nice that motorola ships 
> linux-based cellphones, but they made really sure that users 
> can't hack them... which is considered anti-social by the community. 
> 
> So it would be nice if kernel matched requirements by 
> Motorola, but it is *way* more important that it matches 
> requirements by Sharp and notebook requirements... because 
> Sharp & notebook manufacturers actually play fair.
---

Depends, of course, on your definition of "fair". The CE 
manufacturers are investing a lot of work in Linux, either
directly or through hiring developers and working through
distributors. And they're giving their enhancements back
to the community, which is what was generally considered
"fair" for open-source development. The power management
stuff may be too narrow to be interesting to laptop-based
developers,but things like reduced boot time ought to be
Of more general interest.

I expect modifiable kernels in the future, but that requires
a lot of extra engineering (beyond just making the device
work) to harden the non-open elements so that malicious
kernel changes couldn't compromise them. None of the
manufacturers is going to build a cellphone or DVR that
service providers won't allow on their networks...

scott

Re: OpPoint summary

[Pavel Machek]

Hi!

> >Care to resend your patches in the proper format, through email so that
> >we can see them, and possibly get some testing in -mm if they look sane?
> 
> Greg,
>   here's the patch that implements operating points for different 
>   frequencies
> for the speedstep-centrino line of processors.  Operating points are created
> in much the same manner that cpufreq tables are.  This works for both
> simple implementations like the centrino and more complex SoC systems
> like the arm-pxa72x which has several clocks to control, and different clock
> divisors and multipliers.

> +static struct oppoint lowest = {
> +       .name = "lowest",
> +       .type = PM_FREQ_CHANGE,
> +       .frequency = 0,
> +       .voltage = 0,
> +       .latency = 15,
> +       .prepare_transition  = cpufreq_prepare_transition,
> +       .transition = centrino_transition,
> +       .finish_transition = cpufreq_finish_transition,
> +};

We had nice, descriptive interface... with numbers. Now you want to
introduce english state names... looks like a step back to me.

									Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: community PM requirements/issues and PowerOP[Was: Re: So, what's the status on the recent patches here?]

[Preece Scott-PREECE]

 > From:  Amit Kucheria
> 
> On Sun, 2006-09-17 at 15:40 +0200, ext Pavel Machek wrote:
> > On Sun 2006-09-17 16:28:23, Amit Kucheria wrote:
> > > On Sun, 2006-09-17 at 15:18 +0200, ext Pavel Machek wrote:
...
> > > I was referring to the default method of power save on 
> Zaurus on the 
> > > Sharp ROMs. It was S-T-D (Flash), IIRC. I do not recall drivers 
> > > doing runtime power management on Zaurus; that is a major 
> difference 
> > > from Nokia 770.
> > 
> > I'm pretty sure Zauruses do s-t-ram. Flash is read only 
> during normal 
> > operation.
> > 
> > I'm very sure Sharp zaurus sl-5500 does s-t-ram. After all, it has 
> > 16MB of flash and 64MB of ram. Suspend-to-flash is not an option.
> > 
> > 								Pavel
> 
> If that is the case, I stand corrected. Did the drivers 
> support dynamic idling?
> 
> Although something about the time it took to resume still 
> bothers me....
> I will try to find time to flash it and check.

Google provided a reference to what appears to be a student
paper on power management in the Zaurus, at:
<http://personals.ac.upc.edu/mpericas/zaurus_project-final.pdf#search=%2
2%22power%20management%22%20zaurus%20linux%22>.

>From the paper, it sounds like it has cpufreq 
scaling and a sleep mode that is basically suspend-to-RAM.
This was apparently done via backporting stuff to 2.4.

Scott

Re: [linux-pm] OpPoint summary

[Matthew Locke]

Dave,

I am confused as to why you continue to duplicate work already done in 
PowerOP.  We are still waiting to hear why you need to have a different 
operating point interface.  As Eugeny and I  have pointed out before 
(refer to the thread  in my PowerOP vs OPpoint email), your interface 
doesn't make sense on a mulit cpu, SMP or otherwise, system.  I 
recommend you redo your patches to use PowerOP which already supports 
this properly.


On Sep 16, 2006, at 10:07 PM, David Singleton wrote:

> Pavel and Greg,
>
> I've incorporated Pavels suggestions and only put suspend states
> in the /sys/power/state file.  The control file for frequency and
> voltage operating
> point transitions is now in /sys/power/operating_points/current_point.
>
> The /sys/power/operating_points dirctory still contains the operating
> points themselves, with a frequency, voltage and latency file
> for each operating point.
>
> The oppointd power manager has been changed to use the
> new control file for operating points.  It has been tested on
> a centrino laptop, the 4 way Xeon server and the arm-pxa27x.
>
> I finally got SMP tested on a 4 way Xeon server.  The patch
> that supports SMP Xeon's is the oppoint-x86-p4.patch in the series.
>
> The only files in the core framework patch now are:
>
>         kernel/power/main.c
>         include/linux/pm.h
>         kernel/power/power.h
>
> The full patch set is at
>
>         http://source.mvista.com/~dsingleton/2.6.18-rc7
>
> The power manager source and patch is at:
>
>         http://source.mvista.com/~dsingleton/oppointd-1.2.3
>
> Attached is the oppoint-core.patch.
>
> David
>
> Signed-Off-by: David Singleton <dsingleton@mvista.com>
>
>  include/linux/pm.h   |   30 +++-
>  kernel/power/main.c  |  361 
> +++++++++++++++++++++++++++++++++++++++++++++------
>  kernel/power/power.h |    2
>  3 files changed, 350 insertions(+), 43 deletions(-)
>
> Index: linux-2.6.17/kernel/power/main.c
> ===================================================================
> --- linux-2.6.17.orig/kernel/power/main.c
> +++ linux-2.6.17/kernel/power/main.c
> @@ -16,6 +16,7 @@
>  #include <linux/init.h>
>  #include <linux/pm.h>
>  #include <linux/console.h>
> +#include <linux/module.h>
>
>  #include "power.h"
>
> @@ -49,7 +50,7 @@ void pm_set_ops(struct pm_ops * ops)
>   *     the platform can enter the requested state.
>   */
>
> -static int suspend_prepare(suspend_state_t state)
> +static int suspend_prepare(struct oppoint * state)
>  {
>         int error = 0;
>         unsigned int free_pages;
> @@ -82,7 +83,7 @@ static int suspend_prepare(suspend_state
>         }
>
>         if (pm_ops->prepare) {
> -               if ((error = pm_ops->prepare(state)))
> +               if ((error = pm_ops->prepare(state->type)))
>                         goto Thaw;
>         }
>
> @@ -94,7 +95,7 @@ static int suspend_prepare(suspend_state
>         return 0;
>   Finish:
>         if (pm_ops->finish)
> -               pm_ops->finish(state);
> +               pm_ops->finish(state->type);
>   Thaw:
>         thaw_processes();
>   Enable_cpu:
> @@ -104,7 +105,7 @@ static int suspend_prepare(suspend_state
>  }
>
>
> -int suspend_enter(suspend_state_t state)
> +int suspend_enter(struct oppoint * state)
>  {
>         int error = 0;
>         unsigned long flags;
> @@ -115,7 +116,7 @@ int suspend_enter(suspend_state_t state)
>                 printk(KERN_ERR "Some devices failed to power down\n");
>                 goto Done;
>         }
> -       error = pm_ops->enter(state);
> +       error = pm_ops->enter(state->type);
>         device_power_up();
>   Done:
>         local_irq_restore(flags);
> @@ -131,36 +132,82 @@ int suspend_enter(suspend_state_t state)
>   *     console that we've allocated. This is not called for 
> suspend-to-disk.
>   */
>
> -static void suspend_finish(suspend_state_t state)
> +static void suspend_finish(struct oppoint * state)
>  {
>         device_resume();
>         resume_console();
>         thaw_processes();
>         enable_nonboot_cpus();
>         if (pm_ops && pm_ops->finish)
> -               pm_ops->finish(state);
> +               pm_ops->finish(state->type);
>         pm_restore_console();
>  }
>
> +struct list_head pm_list;
> +static struct oppoint standby = {
> +       .name = "standby",
> +       .type = PM_SUSPEND_STANDBY,
> +};
>
> +static struct oppoint mem = {
> +       .name = "mem",
> +       .type = PM_SUSPEND_MEM,
> +       .frequency = 0,
> +       .voltage = 0,
> +       .latency = 150,
> +};
>
> -
> -static const char * const pm_states[PM_SUSPEND_MAX] = {
> -       [PM_SUSPEND_STANDBY]    = "standby",
> -       [PM_SUSPEND_MEM]        = "mem",
>  #ifdef CONFIG_SOFTWARE_SUSPEND
> -       [PM_SUSPEND_DISK]       = "disk",
> +struct oppoint disk = {
> +       .name = "disk",
> +       .type = PM_SUSPEND_DISK,
> +};
>  #endif
> +
> +struct oppoint pm_states = {
> +       .name = "default",
> +       .type = PM_FREQ_CHANGE,
>  };
> +struct oppoint *current_state;
> +
> +/*
> + *
> + */
> +static int pm_change_state(struct oppoint *state)
> +{
> +       int error = 0;
> +
> +       printk("OpPoint: changing from %s to %s\n", 
> current_state->name,
> +            state->name);
> +       /*
> +        * compare to current operating point.
> +        * if different change to new operating point.
> +        */
> +       if (current_state == state)
> +               goto out;
> +
> +       if ((error = state->prepare_transition(current_state, state)))
> +               goto out;
> +
> +       if ((error = state->transition(current_state, state)))
> +                state = current_state;
> +
> +       if ((error = state->finish_transition(current_state, state)) 
> == 0)
> +               current_state = state;
> +
> +out:
> +       printk("OpPoint: State change returned %d\n", error);
> +       return error;
> +}
>
> -static inline int valid_state(suspend_state_t state)
> +static inline int valid_state(struct oppoint * state)
>  {
>         /* Suspend-to-disk does not really need low-level support.
>          * It can work with reboot if needed. */
> -       if (state == PM_SUSPEND_DISK)
> +       if (state->type == PM_SUSPEND_DISK)
>                 return 1;
>
> -       if (pm_ops && pm_ops->valid && !pm_ops->valid(state))
> +       if (pm_ops && pm_ops->valid && !pm_ops->valid(state->type))
>                 return 0;
>         return 1;
>  }
> @@ -168,7 +215,7 @@ static inline int valid_state(suspend_st
>
>  /**
>   *     enter_state - Do common work of entering low-power state.
> - *     @state:         pm_state structure for state we're entering.
> + *     @state:         oppoint structure for state we're entering.
>   *
>   *     Make sure we're the only ones trying to enter a sleep state. 
> Fail
>   *     if someone has beat us to it, since we don't want anything 
> weird to
> @@ -177,7 +224,7 @@ static inline int valid_state(suspend_st
>   *     we've woken up).
>   */
>
> -static int enter_state(suspend_state_t state)
> +static int enter_state(struct oppoint *state)
>  {
>         int error;
>
> @@ -186,16 +233,21 @@ static int enter_state(suspend_state_t s
>         if (down_trylock(&pm_sem))
>                 return -EBUSY;
>
> -       if (state == PM_SUSPEND_DISK) {
> +       if (state->type == PM_SUSPEND_DISK) {
>                 error = pm_suspend_disk();
>                 goto Unlock;
>         }
>
> -       pr_debug("PM: Preparing system for %s sleep\n", 
> pm_states[state]);
> +       if (state->type == PM_FREQ_CHANGE || state->type == 
> PM_VOLT_CHANGE) {
> +               error = pm_change_state(state);
> +               goto Unlock;
> +       }
> +
> +       pr_debug("PM: Preparing system for %s sleep\n", state->name);
>         if ((error = suspend_prepare(state)))
>                 goto Unlock;
>
> -       pr_debug("PM: Entering %s sleep\n", pm_states[state]);
> +       pr_debug("PM: Entering %s sleep\n", state->name);
>         error = suspend_enter(state);
>
>         pr_debug("PM: Finishing wakeup.\n");
> @@ -211,7 +263,15 @@ static int enter_state(suspend_state_t s
>   */
>  int software_suspend(void)
>  {
> -       return enter_state(PM_SUSPEND_DISK);
> +       struct oppoint *this, *next;
> +       struct list_head *head = &mem.list;
> +       int error = 0;
> +
> +       list_for_each_entry_safe(this, next, head, list) {
> +               if (this->type == PM_SUSPEND_DISK)
> +                       error= enter_state(this);
> +       }
> +       return error;
>  }
>
>
> @@ -223,9 +283,9 @@ int software_suspend(void)
>   *     structure, and enter (above).
>   */
>
> -int pm_suspend(suspend_state_t state)
> +int pm_suspend(struct oppoint * state)
>  {
> -       if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
> +       if (state->type > PM_SUSPEND_ON && state->type <= 
> PM_SUSPEND_MAX)
>                 return enter_state(state);
>         return -EINVAL;
>  }
> @@ -248,36 +308,35 @@ decl_subsys(power,NULL,NULL);
>
>  static ssize_t state_show(struct subsystem * subsys, char * buf)
>  {
> -       int i;
> -       char * s = buf;
> +       struct oppoint *this, *next;
> +       struct list_head *head = &pm_list;
> +       char *s = buf;
> +
> +       list_for_each_entry_safe(this, next, head, list)
> +               s += sprintf(s,"%s ", this->name);
>
> -       for (i = 0; i < PM_SUSPEND_MAX; i++) {
> -               if (pm_states[i] && valid_state(i))
> -                       s += sprintf(s,"%s ", pm_states[i]);
> -       }
>         s += sprintf(s,"\n");
> +
>         return (s - buf);
>  }
>
>  static ssize_t state_store(struct subsystem * subsys, const char *
> buf, size_t n)
>  {
> -       suspend_state_t state = PM_SUSPEND_STANDBY;
> -       const char * const *s;
> +       struct oppoint *this, *next;
> +       struct list_head *head = &mem.list;
>         char *p;
> -       int error;
> +       int error = -EINVAL;
>         int len;
>
>         p = memchr(buf, '\n', n);
>         len = p ? p - buf : n;
> -
> -       for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, 
> state++) {
> -               if (*s && !strncmp(buf, *s, len))
> +       list_for_each_entry_safe(this, next, head, list) {
> +               if ((strlen(this->name) == len) &&
> +                  (!strncmp(this->name, buf, len))) {
> +                       error = enter_state(this);
>                         break;
> +               }
>         }
> -       if (state < PM_SUSPEND_MAX && *s)
> -               error = enter_state(state);
> -       else
> -               error = -EINVAL;
>         return error ? error : n;
>  }
>
> @@ -292,12 +351,234 @@ static struct attribute_group attr_group
>         .attrs = g,
>  };
>
> +static struct kobject oppoint_kobj = {
> +        .kset = &power_subsys.kset,
> +};
> +
> +struct oppoint_attribute {
> +        struct attribute        attr;
> +        ssize_t (*show)(struct kobject * kobj, char * buf);
> +        ssize_t (*store)(struct kobject * kobj, const char * buf,
> size_t count);
> +};
> +
> +#define to_oppoint(obj) container_of(obj,struct oppoint,kobj)
> +#define to_oppoint_attr(_attr) container_of(_attr,struct
> oppoint_attribute,attr)
> +/*
> + * the frequency, voltage and latency files are readonly
> + */
> +
> +static ssize_t oppoint_voltage_show(struct kobject * kobj, char * buf)
> +{
> +       ssize_t len;
> +       struct oppoint *opt = to_oppoint(kobj);
> +
> +       len = sprintf(buf, "%8d\n", opt->voltage);
> +
> +       return len;
> +}
> +
> +static ssize_t oppoint_voltage_store(struct kobject * kobj, const 
> char * buf,
> +       size_t n)
> +{
> +        return -EINVAL;
> +
> +}
> +
> +static ssize_t oppoint_frequency_show(struct kobject * kobj, char * 
> buf)
> +{
> +       ssize_t len;
> +       struct oppoint *opt = to_oppoint(kobj);
> +
> +       len = sprintf(buf, "%8d\n", opt->frequency);
> +
> +       return len;
> +}
> +
> +static ssize_t oppoint_frequency_store(struct kobject * kobj,
> +        const char * buf, size_t n)
> +{
> +        return -EINVAL;
> +
> +}
> +
> +static ssize_t oppoint_point_show(struct kobject * kobj, char * buf)
> +{
> +       ssize_t len;
> +
> +       len = sprintf(buf, "%s\n", current_state->name);
> +
> +       return len;
> +}
> +
> +static ssize_t oppoint_point_store(struct kobject * kobj, const char 
> * buf,
> +       size_t n)
> +{
> +        struct oppoint *this, *next;
> +        struct list_head *head = &pm_states.list;
> +        char *p;
> +        int error = -EINVAL;
> +        int len;
> +
> +        p = memchr(buf, '\n', n);
> +        len = p ? p - buf : n;
> +        list_for_each_entry_safe(this, next, head, list) {
> +                if ((strlen(this->name) == len) &&
> +                   (!strncmp(this->name, buf, len))) {
> +                        error = enter_state(this);
> +                        break;
> +                }
> +        }
> +        return error ? error : n;
> +}
> +
> +static ssize_t oppoint_latency_show(struct kobject * kobj, char * buf)
> +{
> +       ssize_t len;
> +       struct oppoint *opt = to_oppoint(kobj);
> +
> +       len = sprintf(buf, "%8d\n", opt->latency);
> +
> +       return len;
> +}
> +
> +static ssize_t oppoint_latency_store(struct kobject * kobj,
> +        const char * buf, size_t n)
> +{
> +        return -EINVAL;
> +
> +}
> +
> +static struct oppoint_attribute point_attr = {
> +        .attr   = {
> +                .name = "current_point",
> +                .mode = 0600,
> +        },
> +        .show   = oppoint_point_show,
> +        .store  = oppoint_point_store,
> +};
> +
> +static struct oppoint_attribute frequency_attr = {
> +        .attr   = {
> +                .name = "frequency",
> +                .mode = 0400,
> +        },
> +        .show   = oppoint_frequency_show,
> +        .store  = oppoint_frequency_store,
> +};
> +
> +static struct oppoint_attribute voltage_attr = {
> +        .attr   = {
> +                .name = "voltage",
> +                .mode = 0400,
> +        },
> +        .show   = oppoint_voltage_show,
> +        .store  = oppoint_voltage_store,
> +};
> +
> +static struct oppoint_attribute latency_attr = {
> +        .attr   = {
> +                .name = "latency",
> +                .mode = 0400,
> +        },
> +        .show   = oppoint_latency_show,
> +        .store  = oppoint_latency_store,
> +};
> +
> +static ssize_t
> +oppoint_attr_show(struct kobject * kobj, struct attribute * attr, 
> char * buf)
> +{
> +       struct oppoint_attribute * opt_attr = to_oppoint_attr(attr);
> +       ssize_t ret = 0;
> +
> +       if (opt_attr->show)
> +               ret = opt_attr->show(kobj,buf);
> +       return ret;
> +}
> +
> +static ssize_t
> +oppoint_attr_store(struct kobject * kobj, struct attribute * attr,
> +             const char * buf, size_t count)
> +{
> +       return -EINVAL;
> +}
> +
> +static void oppoint_kobj_release(struct kobject *kobj)
> +{
> +       return;
> +}
> +
> +static struct sysfs_ops oppoint_sysfs_ops = {
> +       .show   = oppoint_attr_show,
> +       .store  = oppoint_attr_store,
> +};
> +
> +static struct attribute * oppoint_default_attrs[] = {
> +       &frequency_attr.attr,
> +       &voltage_attr.attr,
> +       &latency_attr.attr,
> +       NULL,
> +};
> +
> +static struct kobj_type ktype_operating_point = {
> +        .release        = oppoint_kobj_release,
> +        .sysfs_ops      = &oppoint_sysfs_ops,
> +        .default_attrs  = oppoint_default_attrs,
> +};
> +
> +int unregister_operating_point(struct oppoint *opt)
> +{
> +       down(&pm_sem);
> +       list_del_init(&opt->list);
> +       sysfs_remove_file(&opt->kobj, &frequency_attr.attr);
> +       sysfs_remove_file(&opt->kobj, &voltage_attr.attr);
> +       sysfs_remove_file(&opt->kobj, &latency_attr.attr);
> +       up(&pm_sem);
> +
> +       return 0;
> +}
> +EXPORT_SYMBOL(unregister_operating_point);
> +
> +int register_operating_point(struct oppoint *opt)
> +{
> +       down(&pm_sem);
> +       kobject_set_name(&opt->kobj, opt->name);
> +       opt->kobj.kset = &power_subsys.kset;
> +       opt->kobj.parent = &oppoint_kobj;
> +       opt->kobj.ktype = &ktype_operating_point;
> +       kobject_register(&opt->kobj);
> +
> +       sysfs_create_file(&opt->kobj, &frequency_attr.attr);
> +       sysfs_create_file(&opt->kobj, &voltage_attr.attr);
> +       sysfs_create_file(&opt->kobj, &latency_attr.attr);
> +
> +       list_add_tail(&opt->list, &pm_states.list);
> +       up(&pm_sem);
> +       return 0;
> +}
> +EXPORT_SYMBOL(register_operating_point);
>
>  static int __init pm_init(void)
>  {
> +
>         int error = subsystem_register(&power_subsys);
> -       if (!error)
> +       if (!error) {
>                 error = 
> sysfs_create_group(&power_subsys.kset.kobj,&attr_group);
> +               kobject_set_name(&oppoint_kobj, "operating_points");
> +               kobject_register(&oppoint_kobj);
> +               sysfs_create_file(&oppoint_kobj, &point_attr.attr);
> +       }
> +
> +
> +       INIT_LIST_HEAD(&pm_states.list);
> +       INIT_LIST_HEAD(&pm_list);
> +
> +#ifdef CONFIG_SOFTWARE_SUSPEND
> +       list_add(&disk.list, &pm_list);
> +#endif
> +       list_add(&standby.list, &pm_list);
> +       list_add(&mem.list, &pm_list);
> +       current_state = &pm_states;
> +
>         return error;
>  }
>
> Index: linux-2.6.17/include/linux/pm.h
> ===================================================================
> --- linux-2.6.17.orig/include/linux/pm.h
> +++ linux-2.6.17/include/linux/pm.h
> @@ -24,6 +24,7 @@
>  #ifdef __KERNEL__
>
>  #include <linux/list.h>
> +#include <linux/kobject.h>
>  #include <asm/atomic.h>
>
>  /*
> @@ -108,7 +109,32 @@ typedef int __bitwise suspend_state_t;
>  #define PM_SUSPEND_STANDBY     ((__force suspend_state_t) 1)
>  #define PM_SUSPEND_MEM         ((__force suspend_state_t) 3)
>  #define PM_SUSPEND_DISK                ((__force suspend_state_t) 4)
> -#define PM_SUSPEND_MAX         ((__force suspend_state_t) 5)
> +#define PM_FREQ_CHANGE         ((__force suspend_state_t) 5)
> +#define PM_VOLT_CHANGE         ((__force suspend_state_t) 6)
> +#define PM_SUSPEND_MAX         ((__force suspend_state_t) 7)
> +
> +struct oppoint {
> +       struct list_head list;
> +       suspend_state_t type;
> +       char *name;
> +       unsigned int flags;
> +       unsigned int frequency;         /* in KHz */
> +       unsigned int voltage;           /* mV */
> +       unsigned int latency;           /* transition latency in us */
> +       int     (*prepare_transition)(struct oppoint *cur, struct 
> oppoint *new);
> +       int     (*transition)(struct oppoint *cur, struct oppoint 
> *new);
> +       int     (*finish_transition)(struct oppoint *cur, struct 
> oppoint *new);
> +
> +       void *md_data;                  /* arch dependent data */
> +       struct kobject kobj;
> +};
> +
> +
> +extern struct oppoint pm_states;
> +extern struct oppoint *current_state;
> +extern int register_operating_point(struct oppoint *opt);
> +extern int unregister_operating_point(struct oppoint *opt);
> +struct notifier_block;
>
>  typedef int __bitwise suspend_disk_method_t;
>
> @@ -128,7 +154,7 @@ struct pm_ops {
>
>  extern void pm_set_ops(struct pm_ops *);
>  extern struct pm_ops *pm_ops;
> -extern int pm_suspend(suspend_state_t state);
> +extern int pm_suspend(struct oppoint *state);
>
>
>  /*
> Index: linux-2.6.17/kernel/power/power.h
> ===================================================================
> --- linux-2.6.17.orig/kernel/power/power.h
> +++ linux-2.6.17/kernel/power/power.h
> @@ -113,4 +113,4 @@ extern int swsusp_resume(void);
>  extern int swsusp_read(void);
>  extern int swsusp_write(void);
>  extern void swsusp_close(void);
> -extern int suspend_enter(suspend_state_t state);
> +extern int suspend_enter(struct oppoint * state);
> _______________________________________________
> linux-pm mailing list
> linux-pm@lists.osdl.org
> https://lists.osdl.org/mailman/listinfo/linux-pm
>

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Pavel Machek]

> (Modified recipient list)

> > I'm pretty sure Zauruses do s-t-ram. Flash is read only during normal
> > operation.
> > 
> > I'm very sure Sharp zaurus sl-5500 does s-t-ram. After all, it has
> > 16MB of flash and 64MB of ram. Suspend-to-flash is not an option.
> 
> If that is the case, I stand corrected. Did the drivers support dynamic
> idling?

Not sure about that one.

> Although something about the time it took to resume still bothers me....
> I will try to find time to flash it and check.

Well, in 2.6.X suspend-to-RAM means console switch and process
freezing. (Yes, it would be nice to fix that).
								Pavel

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Amit Kucheria]

On Sun, 2006-09-17 at 14:34 +0200, ext Pavel Machek wrote:

> > OMAP1 hardware is easily had; an OSK, or a Nokia N770.  The latter is
> > battery powered already, without the hardware mods...
> 
> Well, I already have zaurus, and nokia 770 is inferior AFAICT. So the
> next one will be linux cellphone...
> 
> (And IIRC zaurus lasts longer on batteries than 770 does... or at
> least comparable. Maybe OMAP is more complex, but is it actually good
> thing?)
> 								Pavel

Wifi + Significantly higher resolution display tend to play a 'small'
role in this.

-- 
Amit Kucheria <amit.kucheria@nokia.com>
Nokia

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Pavel Machek]

On Mon 2006-09-18 13:46:04, Amit Kucheria wrote:
> On Sun, 2006-09-17 at 14:34 +0200, ext Pavel Machek wrote:
> 
> > > OMAP1 hardware is easily had; an OSK, or a Nokia N770.  The latter is
> > > battery powered already, without the hardware mods...
> > 
> > Well, I already have zaurus, and nokia 770 is inferior AFAICT. So the
> > next one will be linux cellphone...
> > 
> > (And IIRC zaurus lasts longer on batteries than 770 does... or at
> > least comparable. Maybe OMAP is more complex, but is it actually good
> > thing?)
> 
> Wifi + Significantly higher resolution display tend to play a 'small'
> role in this.

640x480 display vs. 800x480 display does not sound like _that_ big
deal to me. You are right with wifi, that beasts eat 1W-or-so. (and it
would be great if someone implemented wifi power saving...)

								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Igor Stoppa]

On Mon, 2006-09-18 at 12:53 +0200, ext Pavel Machek wrote:
> On Mon 2006-09-18 13:46:04, Amit Kucheria wrote:
> > On Sun, 2006-09-17 at 14:34 +0200, ext Pavel Machek wrote:
> > 
> > > > OMAP1 hardware is easily had; an OSK, or a Nokia N770.  The latter is
> > > > battery powered already, without the hardware mods...
> > > 
> > > Well, I already have zaurus, and nokia 770 is inferior AFAICT. So the
> > > next one will be linux cellphone...
> > > 
> > > (And IIRC zaurus lasts longer on batteries than 770 does... or at
> > > least comparable. Maybe OMAP is more complex, but is it actually good
> > > thing?)
> > 
> > Wifi + Significantly higher resolution display tend to play a 'small'
> > role in this.
> 
> 640x480 display vs. 800x480 display does not sound like _that_ big
> deal to me. You are right with wifi, that beasts eat 1W-or-so. (and it
> would be great if someone implemented wifi power saving...)
> 
> 								Pavel

wifi power saving does exist and you have it already in 770
and also color depth probably affects performance: do they have the same
number of bits per pixel?
-- 
Cheers,
           Igor

Igor Stoppa (Nokia M - OSSO / Tampere)

nokia 770 [was Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]]

[Pavel Machek]

On Mon 2006-09-18 15:01:15, Igor Stoppa wrote:
> On Mon, 2006-09-18 at 12:53 +0200, ext Pavel Machek wrote:
> > On Mon 2006-09-18 13:46:04, Amit Kucheria wrote:
> > > On Sun, 2006-09-17 at 14:34 +0200, ext Pavel Machek wrote:

> > > > (And IIRC zaurus lasts longer on batteries than 770 does... or at
> > > > least comparable. Maybe OMAP is more complex, but is it actually good
> > > > thing?)
> > > 
> > > Wifi + Significantly higher resolution display tend to play a 'small'
> > > role in this.
> > 
> > 640x480 display vs. 800x480 display does not sound like _that_ big
> > deal to me. You are right with wifi, that beasts eat 1W-or-so. (and it
> > would be great if someone implemented wifi power saving...)
> 
> wifi power saving does exist and you have it already in 770
> and also color depth probably affects performance: do they have the same
> number of bits per pixel?

Not sure, but I believe it has 65000 colors.

What wireless chip is included in 770? Are you using devicespace
stack? Is wifi driver opensource?
								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: nokia 770 [was Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]]

[Amit Kucheria]

On Mon, 2006-09-18 at 14:11 +0200, ext Pavel Machek wrote:
> On Mon 2006-09-18 15:01:15, Igor Stoppa wrote:
> > On Mon, 2006-09-18 at 12:53 +0200, ext Pavel Machek wrote:
> > > On Mon 2006-09-18 13:46:04, Amit Kucheria wrote:
> > > > On Sun, 2006-09-17 at 14:34 +0200, ext Pavel Machek wrote:
> 
> > > > > (And IIRC zaurus lasts longer on batteries than 770 does... or at
> > > > > least comparable. Maybe OMAP is more complex, but is it actually good
> > > > > thing?)
> > > > 
> > > > Wifi + Significantly higher resolution display tend to play a 'small'
> > > > role in this.
> > > 
> > > 640x480 display vs. 800x480 display does not sound like _that_ big
> > > deal to me. You are right with wifi, that beasts eat 1W-or-so. (and it
> > > would be great if someone implemented wifi power saving...)
> > 
> > wifi power saving does exist and you have it already in 770
> > and also color depth probably affects performance: do they have the same
> > number of bits per pixel?
> 
> Not sure, but I believe it has 65000 colors.
> 
> What wireless chip is included in 770? Are you using devicespace
> stack? Is wifi driver opensource?
> 								Pavel

It is similar to other 'open-sourced' drivers - binary firmware, open
source driver.

Anyways... this is getting off-topic. Sharp Zaurus was great hardware,
but its not shipped in USA/Europe anymore.

And if the only criteria for hardware-that-matters is hackability, then
Nokia 770 can be flashed with your own kernel and rootfs. Check
www.maemo.org

Regards,
Amit

-- 
Amit Kucheria <amit.kucheria@nokia.com>
Nokia

Re: [linux-pm] OpPoint summary

[Richard A. Griffiths]

On Sun, 2006-09-17 at 19:48 +0200, Pavel Machek wrote:
> Hi!
> 
> > >Care to resend your patches in the proper format, through email so that
> > >we can see them, and possibly get some testing in -mm if they look sane?
> > 
> > Greg,
> >   here's the patch that implements operating points for different 
> >   frequencies
> > for the speedstep-centrino line of processors.  Operating points are created
> > in much the same manner that cpufreq tables are.  This works for both
> > simple implementations like the centrino and more complex SoC systems
> > like the arm-pxa72x which has several clocks to control, and different clock
> > divisors and multipliers.
> 
> > +static struct oppoint lowest = {
> > +       .name = "lowest",
> > +       .type = PM_FREQ_CHANGE,
> > +       .frequency = 0,
> > +       .voltage = 0,
> > +       .latency = 15,
> > +       .prepare_transition  = cpufreq_prepare_transition,
> > +       .transition = centrino_transition,
> > +       .finish_transition = cpufreq_finish_transition,
> > +};
> 
> We had nice, descriptive interface... with numbers. Now you want to
> introduce english state names... looks like a step back to me.

Maybe a compromise could be reached where a defined set of numbers maps
to  string names ala Unix init states. Many people (at least me) still
invoke init 6 to reboot a system.  A defined table would satisfy both
the number and string camps.

Richard

Re: [linux-pm] OpPoint summary

[Matthew Locke]

On Sep 18, 2006, at 7:33 AM, Richard A. Griffiths wrote:

> On Sun, 2006-09-17 at 19:48 +0200, Pavel Machek wrote:
>> Hi!
>>
>>>> Care to resend your patches in the proper format, through email so 
>>>> that
>>>> we can see them, and possibly get some testing in -mm if they look 
>>>> sane?
>>>
>>> Greg,
>>>   here's the patch that implements operating points for different
>>>   frequencies
>>> for the speedstep-centrino line of processors.  Operating points are 
>>> created
>>> in much the same manner that cpufreq tables are.  This works for both
>>> simple implementations like the centrino and more complex SoC systems
>>> like the arm-pxa72x which has several clocks to control, and 
>>> different clock
>>> divisors and multipliers.
>>
>>> +static struct oppoint lowest = {
>>> +       .name = "lowest",
>>> +       .type = PM_FREQ_CHANGE,
>>> +       .frequency = 0,
>>> +       .voltage = 0,
>>> +       .latency = 15,
>>> +       .prepare_transition  = cpufreq_prepare_transition,
>>> +       .transition = centrino_transition,
>>> +       .finish_transition = cpufreq_finish_transition,
>>> +};
>>
>> We had nice, descriptive interface... with numbers. Now you want to
>> introduce english state names... looks like a step back to me.
>
> Maybe a compromise could be reached where a defined set of numbers maps
> to  string names ala Unix init states. Many people (at least me) still
> invoke init 6 to reboot a system.  A defined table would satisfy both
> the number and string camps.

PowerOP allows the platform to define the name. In our cpufreq 
integration patches, we reuse the same name that cpufreq centrino used.

>
> Richard
> _______________________________________________
> linux-pm mailing list
> linux-pm@lists.osdl.org
> https://lists.osdl.org/mailman/listinfo/linux-pm
>

Re: OpPoint summary

[Matthew Locke]

On Sep 18, 2006, at 7:33 AM, Richard A. Griffiths wrote:

> On Sun, 2006-09-17 at 19:48 +0200, Pavel Machek wrote:
>> Hi!
>>
>>>> Care to resend your patches in the proper format, through email so 
>>>> that
>>>> we can see them, and possibly get some testing in -mm if they look 
>>>> sane?
>>>
>>> Greg,
>>>   here's the patch that implements operating points for different
>>>   frequencies
>>> for the speedstep-centrino line of processors.  Operating points are 
>>> created
>>> in much the same manner that cpufreq tables are.  This works for both
>>> simple implementations like the centrino and more complex SoC systems
>>> like the arm-pxa72x which has several clocks to control, and 
>>> different clock
>>> divisors and multipliers.
>>
>>> +static struct oppoint lowest = {
>>> +       .name = "lowest",
>>> +       .type = PM_FREQ_CHANGE,
>>> +       .frequency = 0,
>>> +       .voltage = 0,
>>> +       .latency = 15,
>>> +       .prepare_transition  = cpufreq_prepare_transition,
>>> +       .transition = centrino_transition,
>>> +       .finish_transition = cpufreq_finish_transition,
>>> +};
>>
>> We had nice, descriptive interface... with numbers. Now you want to
>> introduce english state names... looks like a step back to me.
>
> Maybe a compromise could be reached where a defined set of numbers maps
> to  string names ala Unix init states. Many people (at least me) still
> invoke init 6 to reboot a system.  A defined table would satisfy both
> the number and string camps.

PowerOP allows the platform to define the name. In our cpufreq 
integration patches, we reuse the same name that cpufreq centrino used.

>
> Richard
> _______________________________________________
> linux-pm mailing list
> linux-pm@lists.osdl.org
> https://lists.osdl.org/mailman/listinfo/linux-pm
>

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Pavel Machek]

Hi!

> > Of course I am unfair. It is nice that motorola ships 
> > linux-based cellphones, but they made really sure that users 
> > can't hack them... which is considered anti-social by the community. 
> > 
> > So it would be nice if kernel matched requirements by 
> > Motorola, but it is *way* more important that it matches 
> > requirements by Sharp and notebook requirements... because 
> > Sharp & notebook manufacturers actually play fair.
> ---
> 
> Depends, of course, on your definition of "fair". The CE 
> manufacturers are investing a lot of work in Linux, either
> directly or through hiring developers and working through
> distributors. And they're giving their enhancements back
> to the community, which is what was generally considered
> "fair" for open-source development. The power management

Well, CE equipment usually uses obsolete, heavily modified kernels,
and developed in-house (as opposed by community). Yes, it is nice that
Motorola uses Linux and not WindowsCE...

> stuff may be too narrow to be interesting to laptop-based
> developers,but things like reduced boot time ought to be
> Of more general interest.

Yep, boottime reductions are always nice... if they are not too specialized.

> I expect modifiable kernels in the future, but that requires
> a lot of extra engineering (beyond just making the device
> work) to harden the non-open elements so that malicious
> kernel changes couldn't compromise them. None of the

What is the issue here? I thought that GSM stack runs on separate CPU,
anyway? And in practice, it is probably possible to flash your
equipment... Like small shops offering "unlocking" do it all the time.

> manufacturers is going to build a cellphone or DVR that
> service providers won't allow on their networks...

What is the issue? I can do whatever I want (including modifying
phone-side firmware so that phone works without SIMcard, just with Ki)
with siemens ME45 already. Of course Siemens will not support me doing
that... That should not be too different with Motorola...?
								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: nokia 770 [was Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]]

[Pavel Machek]

Hi!

> > > > 640x480 display vs. 800x480 display does not sound like _that_ big
> > > > deal to me. You are right with wifi, that beasts eat 1W-or-so. (and it
> > > > would be great if someone implemented wifi power saving...)
> > > 
> > > wifi power saving does exist and you have it already in 770
> > > and also color depth probably affects performance: do they have the same
> > > number of bits per pixel?
> > 
> > Not sure, but I believe it has 65000 colors.
> > 
> > What wireless chip is included in 770? Are you using devicespace
> > stack? Is wifi driver opensource?
> 
> It is similar to other 'open-sourced' drivers - binary firmware, open
> source driver.

Ok.

> Anyways... this is getting off-topic. Sharp Zaurus was great hardware,
> but its not shipped in USA/Europe anymore.

Agreed, this is getting off-topic.

> And if the only criteria for hardware-that-matters is hackability, then
> Nokia 770 can be flashed with your own kernel and rootfs. Check
> www.maemo.org

I agree that Nokia is doing the right thing (tm) here (and
THANKS!). (Excluding charging circuity, but someone is going to fix
that). Unfortunately Motorola is not doing the right thing...

Could you perhaps provide list of operating points for 770? It would
help understanding a bit, I'd say.
									Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Preece Scott-PREECE]

> From: Pavel Machek [mailto:pavel@ucw.cz] 
> 
> ... because Sharp & notebook manufacturers 
> > > actually play fair.
> > ---
> > 
> > Depends, of course, on your definition of "fair". The CE 
> manufacturers 
> > are investing a lot of work in Linux, either directly or through 
> > hiring developers and working through distributors. And 
> they're giving 
> > their enhancements back to the community, which is what was 
> generally 
> > considered "fair" for open-source development. The power management
> 
> Well, CE equipment usually uses obsolete, heavily modified 
> kernels, and developed in-house (as opposed by community). 
> Yes, it is nice that Motorola uses Linux and not WindowsCE...
---

There are perfectly sensible business reasons why device manufacturers
need to freeze their development on old kernels (and other components)
for long periods of time. Are you saying this is "unfair" to the
developers? I understand that it makes the patches less useful, in
many cases, but unfair?

I do hope that Motorola, and other CE manufacturers, will start working
more closely with the community.  The CE Linux Forum was set up in part
to make that easier and more effective. I believe it would be better 
for both the manufacturers and the community.

---
> ... 
> > I expect modifiable kernels in the future, but that 
> requires a lot of 
> > extra engineering (beyond just making the device
> > work) to harden the non-open elements so that malicious 
> kernel changes 
> > couldn't compromise them. None of the
> 
> What is the issue here? I thought that GSM stack runs on 
> separate CPU, anyway? And in practice, it is probably 
> possible to flash your equipment... Like small shops offering 
> "unlocking" do it all the time.
---
[NOTE again that I do not speak for Motorola in this mailing list;
these comments are not based on direct knowledge of policy, and
IANAL!]

The issue is "due diligence" - a manufacturer could be held liable
for damage done by a modified device if they have not made a good
faith effort to make such modification either (a) safe or
(b) very difficult. Yes, this is non-value-add work, but there are
people in the world who do malicious things, and manufacturers are
very worried about courts finding that they were negligent in
not making a greater effort to stop such malicious people.

There is also a liability issue with non-malicious changes, in that
manufacturers can sometimes be held liable for things that users
do to themselves. [If you believe that disclaimers of liability or 
warranty will actually protect you in court, you're probably 
being naïve.]

There are also, of course, contractual issues with carriers and
content owners, who could also sue if a manufacturer didn't make a
sufficient effort to protect the terms of the contract. The
carriers and content owners are continually raising the bar on the
level of protection they require.

---
> 
> > manufacturers is going to build a cellphone or DVR that service 
> > providers won't allow on their networks...
> 
> What is the issue? I can do whatever I want (including 
> modifying phone-side firmware so that phone works without 
> SIMcard, just with Ki) with siemens ME45 already. Of course 
> Siemens will not support me doing that... That should not be 
> too different with Motorola...?
---

While legal specifics may vary from country to country, for US
Manufacturers, the same issues as above...

scott

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Pavel Machek]

Hi!

> > ... because Sharp & notebook manufacturers 
> > > > actually play fair.
> > > ---
> > > 
> > > Depends, of course, on your definition of "fair". The CE 
> > manufacturers 
> > > are investing a lot of work in Linux, either directly or through 
> > > hiring developers and working through distributors. And 
> > they're giving 
> > > their enhancements back to the community, which is what was 
> > generally 
> > > considered "fair" for open-source development. The power management
> > 
> > Well, CE equipment usually uses obsolete, heavily modified 
> > kernels, and developed in-house (as opposed by community). 
> > Yes, it is nice that Motorola uses Linux and not WindowsCE...
> ---
> 
> There are perfectly sensible business reasons why device manufacturers
> need to freeze their development on old kernels (and other components)
> for long periods of time. Are you saying this is "unfair" to the
> developers? I understand that it makes the patches less useful, in
> many cases, but unfair?

No, I call "you may not use your own kernel on your own hardware",
even if manufacturer of that hardware is using your code and code is
GPLed "unfair". Being locked onto old kernel is unfortunate, but fair.

> I do hope that Motorola, and other CE manufacturers, will start working
> more closely with the community.  The CE Linux Forum was set up in

Yep, I hope so, too.

> > ... 
> > > I expect modifiable kernels in the future, but that 
> > requires a lot of 
> > > extra engineering (beyond just making the device
> > > work) to harden the non-open elements so that malicious 
> > kernel changes 
> > > couldn't compromise them. None of the
> > 
> > What is the issue here? I thought that GSM stack runs on 
> > separate CPU, anyway? And in practice, it is probably 
> > possible to flash your equipment... Like small shops offering 
> > "unlocking" do it all the time.
> 
> The issue is "due diligence" - a manufacturer could be held liable
> for damage done by a modified device if they have not made a good
> faith effort to make such modification either (a) safe or
> (b) very difficult. Yes, this is non-value-add work, but there are
> people in the world who do malicious things, and manufacturers are
> very worried about courts finding that they were negligent in
> not making a greater effort to stop such malicious people.

Well, I believe Motorola is going a bit further than "due
diligence". Making directories inaccessible on running system (not
even read only!) was probably not mandatory, right? And even M$
smartphones support end-user updating of firmware.

> There are also, of course, contractual issues with carriers and
> content owners, who could also sue if a manufacturer didn't make a
> sufficient effort to protect the terms of the contract. The
> carriers and content owners are continually raising the bar on the
> level of protection they require.

Yep, I see it sucks being phone manufacturer. But you have separate
CPU doing GSM stack in current cellphones, right? I believe you even
use AT commands for communication... That should be about as hard as
pcmcia card to "harden", and yes, people are routinelly selling pcmcia
GSM cards.

								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

[Dominik Brodowski]

Hi,

Just to set the record straight:

On Tue, Sep 12, 2006 at 02:05:26AM +0400, Eugeny S. Mints wrote:
> Cpuferq defines cpufreq_frequency_table structure in arch independent header 
> while it's arch dependent data structure.

cpufreq_frequency_table is an _optional_ library architectures _may_ use if
they consider it useful to them. It's useful for most of them, but it is not
required at the core level. For a reason.

> A lot of code is built around this 
> invalid basic brick and therefore is invalid: cpufreq tables, interface with cpu 
> freq drivers, etc.

cpufreq tables? what do you mean with that?

And the interface with cpufreq drivers does not rely on
cpufreq_frequency_table. That's one of the fun things in cpufreq. You don't
need to define a pre-defined table for the >10^5 states at least one cpufreq
driver offers.

> Notion of transition latency as it defined by cpufreq is 
> wrong because it's not a function of cpu type but function of current and next 
> operating point.

That may be, but it may serve as the "maximum latency" at the moment; if
needed, it could be expanded, e.g. using or on top of the interfaces
described in http://lwn.net/Articles/197299/ .

> no runtime control on operating points set. it's always the 
> same set of operating points for all system cpus in smp case and no way to 
> define different sets or track any dependencies in case say multi core cpus. 

You can define different min, current, and max frequencies (for this is all
the cpufreq core cares about) for multiple cores. How the freq_table
interactions work then, I cannot say without checking the source -- but as
it is only an _optional_ library an arch can use, that doesn't count.

> insufficient kernel<->user space interface to handle embedded requirements and 
> no way to extend it within current design.

Nobody tried to do so yet, to my knowledge.

> PowerOP/cufreq integration patch set contains very details explanation of the 
> cpufreq design issues and POwerOP solutions. Comment there is you feel it's wrong.

I'll gladly do so soon, and I'll also comment further on the PowerOP patches -- but
not today, sorry.


Thanks,
	Dominik

Re: nokia 770 [was Re: community PM requirements/issues and PowerOP]

[David Brownell]

On Tuesday 19 September 2006 11:25 am, Pavel Machek wrote:
> 
> Could you perhaps provide list of operating points for 770? It would
> help understanding a bit, I'd say.

If there was a followup here, I missed it ...

ISTR that it doesn't use (formal) operating points, and that a lot of the
basic SOC power savings (vs powering off the display or wifi) come from a
different kind of mechanism entirely.  Namely, a combination of dynamic
tick with a modified system idle task, which enters one of the OMAP low
power modes during those long periods between clock ticks or other irqs.

That's one of the standard power saving schemes used on OMAP1 platforms
with Linux.

- Dave

Re: nokia 770 [was Re: community PM requirements/issues and PowerOP]

[Eugeny S. Mints]

David Brownell wrote:
> On Tuesday 19 September 2006 11:25 am, Pavel Machek wrote:
>> Could you perhaps provide list of operating points for 770? It would
>> help understanding a bit, I'd say.
> 
> If there was a followup here, I missed it ...
> 
> ISTR that it doesn't use (formal) operating points, and that a lot of the
> basic SOC power savings (vs powering off the display or wifi) come from a
> different kind of mechanism entirely.  Namely, a combination of dynamic
> tick with a modified system idle task, which enters one of the OMAP low
> power modes during those long periods between clock ticks or other irqs.
> 
> That's one of the standard power saving schemes used on OMAP1 platforms
> with Linux.
sample of reasonable operating points for OMAP1 platforms along with appropriate 
patches may be found at http://dynamicpower.sourceforge.net/dpm-omap.html

Eugeny
> 
> - Dave
> _______________________________________________
> linux-pm mailing list
> linux-pm@lists.osdl.org
> https://lists.osdl.org/mailman/listinfo/linux-pm
> 

Re: nokia 770 [was Re: community PM requirements/issues and PowerOP]

[Pavel Machek]

On Wed 2006-12-13 15:12:07, Eugeny S. Mints wrote:
> David Brownell wrote:
> > On Tuesday 19 September 2006 11:25 am, Pavel Machek wrote:
> >> Could you perhaps provide list of operating points for 770? It would
> >> help understanding a bit, I'd say.
> > 
> > If there was a followup here, I missed it ...
> > 
> > ISTR that it doesn't use (formal) operating points, and that a lot of the
> > basic SOC power savings (vs powering off the display or wifi) come from a
> > different kind of mechanism entirely.  Namely, a combination of dynamic
> > tick with a modified system idle task, which enters one of the OMAP low
> > power modes during those long periods between clock ticks or other irqs.
> > 
> > That's one of the standard power saving schemes used on OMAP1 platforms
> > with Linux.

> sample of reasonable operating points for OMAP1 platforms along with appropriate 
> patches may be found at http://dynamicpower.sourceforge.net/dpm-omap.html

Okay... so you have system with 4 different cpu speeds. That should be
simple enough to get running using cpufreq, no need for complex
operating points patches.
								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: nokia 770 [was Re: community PM requirements/issues and PowerOP]

[Matthew Locke]

On Dec 12, 2006, at 12:00 PM, David Brownell wrote:

> On Tuesday 19 September 2006 11:25 am, Pavel Machek wrote:
>>
>> Could you perhaps provide list of operating points for 770? It would
>> help understanding a bit, I'd say.
>
> If there was a followup here, I missed it ...

I think there was some sort of followup but I don't think it  
explictly listed the operating point values.
>
> ISTR that it doesn't use (formal) operating points, and that a lot  
> of the
> basic SOC power savings (vs powering off the display or wifi) come  
> from a
> different kind of mechanism entirely.  Namely, a combination of  
> dynamic
> tick with a modified system idle task, which enters one of the OMAP  
> low
> power modes during those long periods between clock ticks or other  
> irqs.
>
> That's one of the standard power saving schemes used on OMAP1  
> platforms
> with Linux.

Well sure but I think this discussion was about using the 770 as a  
specific example of operating point values.  Here are the operating  
points used on omap1.  The board specific part is just whether or not  
the board has a scalable voltage regulator.  Omap1 has a fairly  
simple operating point definition and is, of course, not the latest h/w.

This table comes from the DPM implementation on OMAP1 and is  
expressed as dividers.

Name	Voltage, DPLL multiplier, DPLL divider, cpu divider, tc divider  
(mem bus).

  192        	1300 16 1 1  2
  168        	1300 14 1 1  2
  84			1300 14 1 2  2
  84-1.1v   	1050 14 1 2  2
  60         		1300  5 1 1  1
  60-1.1v    	1050  5 1 1  1
  sleep-168  	1300 14 1 0 -1
  sleep-60   	1300  1 2 0  2

Several other parameters could be added such as dsp and dsp mmu if  
one wanted to do more aggressive power management.  btw, the  
parameter names I list above are from memory so I might have the  
order mixed up but you get the idea.

The dpm utilities on sf.net also include 8 example operating points  
for pxa272.  The operating point definition on pxa has ~5 parameters  
including voltage, cpu frequency and other clocks.



>
> - Dave
> _______________________________________________
> linux-pm mailing list
> linux-pm@lists.osdl.org
> https://lists.osdl.org/mailman/listinfo/linux-pm

Re: nokia 770 [was Re: community PM requirements/issues and PowerOP]

[David Brownell]

On Wednesday 13 December 2006 1:03 pm, Pavel Machek wrote:
> On Wed 2006-12-13 15:12:07, Eugeny S. Mints wrote:
> > David Brownell wrote:
> > > On Tuesday 19 September 2006 11:25 am, Pavel Machek wrote:
> > >> Could you perhaps provide list of operating points for 770? It would
> > >> help understanding a bit, I'd say.
> > > 
> > > If there was a followup here, I missed it ...
> > > 
> > > ISTR that it doesn't use (formal) operating points, and that a lot of the
> > > basic SOC power savings (vs powering off the display or wifi) come from a
> > > different kind of mechanism entirely.  Namely, a combination of dynamic
> > > tick with a modified system idle task, which enters one of the OMAP low
> > > power modes during those long periods between clock ticks or other irqs.
> > > 
> > > That's one of the standard power saving schemes used on OMAP1 platforms
> > > with Linux.
> 
> > sample of reasonable operating points for OMAP1 platforms along with appropriate 
> > patches may be found at http://dynamicpower.sourceforge.net/dpm-omap.html

That's the old DPM stuff not any of the newer proposals right?

I thought the question was specifically what N770 used.


> Okay... so you have system with 4 different cpu speeds. That should be
> simple enough to get running using cpufreq, no need for complex
> operating points patches.

And OMAP1 does have cpufreq support.  I believe that if I checked it out
I'd find that it's used on N770, as a good way to kick in low voltage
operation modes.

... that's in addition to the reduced power idle, which didn't seem to
fit into the DPM framework in any obvious way.

- Dave

Re: nokia 770 [was Re: community PM requirements/issues and PowerOP]

[Matthew Locke]

On Dec 13, 2006, at 1:32 PM, David Brownell wrote:

> On Wednesday 13 December 2006 1:03 pm, Pavel Machek wrote:
>> On Wed 2006-12-13 15:12:07, Eugeny S. Mints wrote:
>>> David Brownell wrote:
>>>> On Tuesday 19 September 2006 11:25 am, Pavel Machek wrote:
>>>>> Could you perhaps provide list of operating points for 770? It  
>>>>> would
>>>>> help understanding a bit, I'd say.
>>>>
>>>> If there was a followup here, I missed it ...
>>>>
>>>> ISTR that it doesn't use (formal) operating points, and that a  
>>>> lot of the
>>>> basic SOC power savings (vs powering off the display or wifi)  
>>>> come from a
>>>> different kind of mechanism entirely.  Namely, a combination of  
>>>> dynamic
>>>> tick with a modified system idle task, which enters one of the  
>>>> OMAP low
>>>> power modes during those long periods between clock ticks or  
>>>> other irqs.
>>>>
>>>> That's one of the standard power saving schemes used on OMAP1  
>>>> platforms
>>>> with Linux.
>>
>>> sample of reasonable operating points for OMAP1 platforms along  
>>> with appropriate
>>> patches may be found at http://dynamicpower.sourceforge.net/dpm- 
>>> omap.html
>
> That's the old DPM stuff not any of the newer proposals right?

Example operating points were requested.  Using the operating points  
from DPM is fine for examples.

>
> I thought the question was specifically what N770 used.

Answered this in my other email.

>
>
>> Okay... so you have system with 4 different cpu speeds. That  
>> should be
>> simple enough to get running using cpufreq, no need for complex
>> operating points patches.
>
> And OMAP1 does have cpufreq support.  I believe that if I checked  
> it out
> I'd find that it's used on N770, as a good way to kick in low voltage
> operation modes.

Except that cpufreq doesn't really support voltage changes and N770  
doesn't have the h/w to change voltage.

>
> ... that's in addition to the reduced power idle, which didn't seem to
> fit into the DPM framework in any obvious way.

Actually, automatically reducing power at idle is what DPM is all  
about.  In DPM an operating point is mapped to the idle state so when  
the idle task is entered an operating point change is triggered.  The  
system can choose the best point for the idle task based on latency  
requirements, length of idle when using dynamic ticks, etc.

>
> - Dave

Re: nokia 770 [was Re: community PM requirements/issues and PowerOP]

[Dave Jones]

On Wed, Dec 13, 2006 at 01:44:02PM -0800, Matthew Locke wrote:

 > > I'd find that it's used on N770, as a good way to kick in low voltage
 > > operation modes.
 > 
 > Except that cpufreq doesn't really support voltage changes

The majority of cpufreq drivers in the tree right now support
voltage scaling just fine.

		Dave

-- 
http://www.codemonkey.org.uk

Re: nokia 770 [was Re: community PM requirements/issues and PowerOP]

[Eugeny S. Mints]

David Brownell wrote:
> On Wednesday 13 December 2006 1:03 pm, Pavel Machek wrote:
>> On Wed 2006-12-13 15:12:07, Eugeny S. Mints wrote:
>>> David Brownell wrote:
>>>> On Tuesday 19 September 2006 11:25 am, Pavel Machek wrote:
>>>>> Could you perhaps provide list of operating points for 770? It would
>>>>> help understanding a bit, I'd say.
>>>> If there was a followup here, I missed it ...
>>>>
>>>> ISTR that it doesn't use (formal) operating points, and that a lot of the
>>>> basic SOC power savings (vs powering off the display or wifi) come from a
>>>> different kind of mechanism entirely.  Namely, a combination of dynamic
>>>> tick with a modified system idle task, which enters one of the OMAP low
>>>> power modes during those long periods between clock ticks or other irqs.
>>>>
>>>> That's one of the standard power saving schemes used on OMAP1 platforms
>>>> with Linux.
>>> sample of reasonable operating points for OMAP1 platforms along with appropriate 
>>> patches may be found at http://dynamicpower.sourceforge.net/dpm-omap.html
> 
> That's the old DPM stuff not any of the newer proposals right?
> 
> I thought the question was specifically what N770 used.
> 
> 
>> Okay... so you have system with 4 different cpu speeds. That should be
>> simple enough to get running using cpufreq, no need for complex
>> operating points patches.
> 
> And OMAP1 does have cpufreq support.  I believe that if I checked it out
> I'd find that it's used on N770, as a good way to kick in low voltage
> operation modes.
> 
> ... that's in addition to the reduced power idle, which didn't seem to
> fit into the DPM framework in any obvious way.
It fits. Omitting some details DPM allows to map/stick operating point to tasks. 
Mapping one of OMAP low power mode operating point to idle task does the job.

Eugeny
> 
> - Dave
> 

Re: nokia 770 [was Re: community PM requirements/issues and PowerOP]

[Pavel Machek]

On Thu 2006-12-14 00:56:24, Eugeny S. Mints wrote:
> David Brownell wrote:
> >On Wednesday 13 December 2006 1:03 pm, Pavel Machek wrote:
> >>On Wed 2006-12-13 15:12:07, Eugeny S. Mints wrote:
> >>>David Brownell wrote:
> >>>>On Tuesday 19 September 2006 11:25 am, Pavel Machek wrote:
> >>>>>Could you perhaps provide list of operating points for 770? It would
> >>>>>help understanding a bit, I'd say.
> >>>>If there was a followup here, I missed it ...
> >>>>
> >>>>ISTR that it doesn't use (formal) operating points, and that a lot of 
> >>>>the
> >>>>basic SOC power savings (vs powering off the display or wifi) come from 
> >>>>a
> >>>>different kind of mechanism entirely.  Namely, a combination of dynamic
> >>>>tick with a modified system idle task, which enters one of the OMAP low
> >>>>power modes during those long periods between clock ticks or other irqs.
> >>>>
> >>>>That's one of the standard power saving schemes used on OMAP1 platforms
> >>>>with Linux.
> >>>sample of reasonable operating points for OMAP1 platforms along with 
> >>>appropriate patches may be found at 
> >>>http://dynamicpower.sourceforge.net/dpm-omap.html
> >
> >That's the old DPM stuff not any of the newer proposals right?
> >
> >I thought the question was specifically what N770 used.
> >
> >
> >>Okay... so you have system with 4 different cpu speeds. That should be
> >>simple enough to get running using cpufreq, no need for complex
> >>operating points patches.
> >
> >And OMAP1 does have cpufreq support.  I believe that if I checked it out
> >I'd find that it's used on N770, as a good way to kick in low voltage
> >operation modes.
> >
> >... that's in addition to the reduced power idle, which didn't seem to
> >fit into the DPM framework in any obvious way.
> It fits. Omitting some details DPM allows to map/stick operating point to 
> tasks. Mapping one of OMAP low power mode operating point to idle task does 
> the job.

That's what I call a hack.

Take a look at acpi C1..C3 state on i386. They provide same
functionality ("reduced power idle"), but they are implemented in
reasonable way and already merged.
								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: nokia 770 [was Re: community PM requirements...]

[David Brownell]

> >> Okay... so you have system with 4 different cpu speeds. That should be
> >> simple enough to get running using cpufreq, no need for complex
> >> operating points patches.
> > 
> > And OMAP1 does have cpufreq support.  I believe that if I checked it out
> > I'd find that it's used on N770, as a good way to kick in low voltage
> > operation modes.

(Of course the 17xx OMAPs already use very low voltage, so systems
using them might not win much by runtime switching of voltage ...)


> > ... that's in addition to the reduced power idle, which didn't seem to
> > fit into the DPM framework in any obvious way.
>
> It fits. Omitting some details DPM allows to map/stick operating point
> to tasks.  Mapping one of OMAP low power mode operating point to idle
> task does the job.

The "operating" points on the web page you referenced did not
include the "Big Sleep" state ... the CPU does not "operate"
there, so that's understandable.

It would be good to have one of the Nokia folk who worked on PM
for the 770 provide a bit more detail.  I'm all but positive it 
doesn't use any incarnation of DPM.  I'm sure that if any numbers
(even rough ones) were available, that'd be very interesting.

Pavel's comment about C2/C3/etc on PCs is relevant in some ways,
but it's also important to remember that many systems don't have
states compatible (in detail, affecting infrastructure) with Intel's
Cx model.  In particular, CPU caches usually won't snoop, so the
constraints associated with cache and DMA interactions won't exist;
but different constraints, e.g clock usage, could easily apply.

- Dave

Re: nokia 770 [was Re: community PM requirements/issues and PowerOP]

[Matthew Locke]

On Dec 13, 2006, at 1:53 PM, Dave Jones wrote:

> On Wed, Dec 13, 2006 at 01:44:02PM -0800, Matthew Locke wrote:
>
>>> I'd find that it's used on N770, as a good way to kick in low  
>>> voltage
>>> operation modes.
>>
>> Except that cpufreq doesn't really support voltage changes
>
> The majority of cpufreq drivers in the tree right now support
> voltage scaling just fine.

Ok, let's reword my sentence.  The cpufreq interface does not support  
voltage as a  parameter which is needed on platforms where you need  
to do more than infer the correct voltage from the requested cpu  
frequency.  Or something like that.  I wasn't challenging the  
existing x86 cpufreq drivers, but the omap cpufreq driver does not  
support voltage scaling.

>
> 		Dave
>
> -- 
> http://www.codemonkey.org.uk

Re: nokia 770 [was Re: community PM requirements...]

[David Brownell]

> >>>> Could you perhaps provide list of operating points for 770? It  
> >>>> would help understanding a bit, I'd say.
> >>>
> >>> If there was a followup here, I missed it ...
> >>>
> >>> ISTR that it doesn't use (formal) operating points, and that ...
> >>
> >>  http://dynamicpower.sourceforge.net/dpm-omap.html
> >
> > That's the old DPM stuff not any of the newer proposals right?
>
> Example operating points were requested.  Using the operating points  
> from DPM is fine for examples.

I read the query to be specifically about operating points
used in that product ... as giving better insight into the
real PM requirements for Linux-based products.

Examples of how one solution _could_ be used address another
purpose than highlighting requirements.


> > ... that's in addition to the reduced power idle, which didn't
> > seem to fit into the DPM framework in any obvious way.
>
> Actually, automatically reducing power at idle is what DPM is all  
> about.  In DPM an operating point is mapped to the idle state so when  
> the idle task is entered an operating point change is triggered.  The  
> system can choose the best point for the idle task based on latency  
> requirements, length of idle when using dynamic ticks, etc.

Hmm, that's something that somehow never came out in previous
discussions.  At least, not to me.  It's possible that the point
did come out, but got buried in all the noise.

So it would appear that an operating point (in DPM, anyway) is
a combination of clock, voltage, and probably other settings,
coupled with an implementation of the idle task and a policy
implemented by idle task ... yes?

Given that the clock API manages clock settings, and cpufreq
(for better or worse) handles CPU-specific clock and voltage,
you can still color me confused about how an "operating point"
would be a programming construct rather than a side effect of
those other APIs on an implementation.  (If anyone wants to
enlighten me, that should go into a new thread!)

- Dave

Re: nokia 770 [was Re: community PM requirements/issues and PowerOP]

[Dave Jones]

On Wed, Dec 13, 2006 at 02:50:12PM -0800, Matthew Locke wrote:
 > 
 > >>> I'd find that it's used on N770, as a good way to kick in low  
 > >>> voltage
 > >>> operation modes.
 > >>
 > >> Except that cpufreq doesn't really support voltage changes
 > >
 > > The majority of cpufreq drivers in the tree right now support
 > > voltage scaling just fine.
 > 
 > Ok, let's reword my sentence.  The cpufreq interface does not support  
 > voltage as a  parameter

Please explain why this is useful at all.
Under what circumstance is "Set the CPU voltage to 1.2V" a useful thing
for a user, sysadmin, or application to do ?

The voltage something runs at is utterly irrelevant to all the above.
Given it's inherently tied to the speed a chip runs at, which makes
a lot more sense for all the above scenarios to change, we export that instead.

AFAICS, exposing voltages to userspace would be completely pointless.

		Dave

-- 
http://www.codemonkey.org.uk

Re: nokia 770 [was Re: community PM requirements/issues and PowerOP]

[Dmitry Krivoschekov]

Dave Jones wrote:

>On Wed, Dec 13, 2006 at 02:50:12PM -0800, Matthew Locke wrote:
> > 
> > >>> I'd find that it's used on N770, as a good way to kick in low  
> > >>> voltage
> > >>> operation modes.
> > >>
> > >> Except that cpufreq doesn't really support voltage changes
> > >
> > > The majority of cpufreq drivers in the tree right now support
> > > voltage scaling just fine.
> > 
> > Ok, let's reword my sentence.  The cpufreq interface does not support  
> > voltage as a  parameter
>
>Please explain why this is useful at all.
>Under what circumstance is "Set the CPU voltage to 1.2V" a useful thing
>for a user, sysadmin, or application to do ?
>  
>
Voltage scaling is a well known technique to reduce power consumption, try
google search "Dynamic voltage scaling" if you are intrested in it.

I agree, in most cases we don't need to scale CPU voltage and frequency
independently since CPU frequency usually coupled with appropriate voltage
to set. But some CPU's permit to choose frequency value for
a given voltage or vice versa, and it makes sense to get a mechanism
to control both voltage and frequency in this case. Some platforms,
Intel Mainstone for example, have external s/w-controlled voltage 
requlators,
that allow to change CPU core voltage in pretty wide range.

Also, CPU is not the only power consumer in the system, you may need to 
scale
voltage for other devices to get a best perfomance/power trade off.
And here is an obvious limitation of cpufreq since it takes care only
about CPU.

Regards,
Dmitry

>The voltage something runs at is utterly irrelevant to all the above.
>Given it's inherently tied to the speed a chip runs at, which makes
>a lot more sense for all the above scenarios to change, we export that instead.
>
>AFAICS, exposing voltages to userspace would be completely pointless.
>
>		Dave
>
>  
>

Re: nokia 770 [was Re: community PM requirements/issues and PowerOP]

[Dave Jones]

On Thu, Dec 14, 2006 at 01:14:13PM +0300, Dmitry Krivoschekov wrote:

 > > > Ok, let's reword my sentence.  The cpufreq interface does not support  
 > > > voltage as a  parameter
 > >
 > >Please explain why this is useful at all.
 > >Under what circumstance is "Set the CPU voltage to 1.2V" a useful thing
 > >for a user, sysadmin, or application to do ?
 > >  
 > >
 > Voltage scaling is a well known technique to reduce power consumption, try
 > google search "Dynamic voltage scaling" if you are intrested in it.

You've missed the point.  I'm well aware of dynamic voltage scaling,
and some of the cpufreq drivers I've written do this.

 > I agree, in most cases we don't need to scale CPU voltage and frequency
 > independently since CPU frequency usually coupled with appropriate voltage
 > to set.

A CPU frequency _always_ has a specific voltage associated with it.

 > But some CPU's permit to choose frequency value for
 > a given voltage or vice versa

But what sense does it make for a user,sysadmin or application
to change voltage?  If any of these want to save power, they do so
by a) doing less work, and then b) lowering the clock speed as this
is inherently tied to voltage.

And if you lower voltage, you *MUST* reduce the frequency anyway.
Running CPUs at higher speeds at lower voltages than those frequencies
are rated for is a fastpath to a crash.

This is one fundamental reason I'm opposed to exporting voltages to userspace.
Because people _will_ get this wrong, and we will see all manner of
strange bugs and crashes reported from people running CPUs at higher
speeds than the voltage is rated for.

By putting this into the hands of userspace, we're setting ourselves up
to fail.  How does userspace/users know what voltage is safe for what frequency?
Without being intimate with the CPU datasheets, they're almost guaranteed
to fail.  The _driver_ needs to know the pairings of voltage/frequency
and export the only thing that makes sense.

 > Also, CPU is not the only power consumer in the system, you may need to 
 > scale voltage for other devices to get a best perfomance/power trade off.
 > And here is an obvious limitation of cpufreq since it takes care only
 > about CPU.

You see it as a limitation, I see it behaving 'as designed'.
If those devices have nothing to do with the CPU, why are they even
relevant to this discussion?

The argument seems to be "cpufreq only cares about CPU frequency, therefore
we need something different".  But, why?  I see no reason why we need
to change cpufreq at all, just add additional interfaces to cover those
other devices, as they're unrelated anyway.   And if there *are* any
devices that are related, they can be tied into the existing cpufreq
drivers just as for eg, the sa1100 drivers scale DRAM timings with CPU speed.

		Dave

-- 
http://www.codemonkey.org.uk

Re: nokia 770 [was Re: community PM requirements/issues and PowerOP]

[Vitaly Wool]

[-- Attachment #1.1: Type: text/plain, Size: 436 bytes --]

On 12/14/06, Dave Jones <davej@redhat.com> wrote:
>
>
> But what sense does it make for a user,sysadmin or application
> to change voltage?  If any of these want to save power, they do so
> by a) doing less work, and then b) lowering the clock speed as this
> is inherently tied to voltage.
>

It makes sense to perform changing an operating point dynamically in
userland.
That said, voltage should be accessible from userland.

Vitaly

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Re: nokia 770 [was Re: community PM requirements/issues and PowerOP]

[Dave Jones]

On Thu, Dec 14, 2006 at 04:01:58PM +0300, Vitaly Wool wrote:
 > On 12/14/06, Dave Jones <davej@redhat.com> wrote:
 > >
 > >
 > > But what sense does it make for a user,sysadmin or application
 > > to change voltage?  If any of these want to save power, they do so
 > > by a) doing less work, and then b) lowering the clock speed as this
 > > is inherently tied to voltage.
 > >
 > 
 > It makes sense to perform changing an operating point dynamically in
 > userland.

An operating point does not have to revolve around the voltage, nor should it.
Fill out the following.

* A sysadmin wants to set the CPU voltage to 1.5V because _________________

* A user wants to set the CPU voltage to 1.5V because _________________

* An application wants to dynamically set the voltage rather than the
  frequency because ______________________


 > That said, voltage should be accessible from userland.

Try again.   It's completely the wrong knob to be turning.

		Dave

-- 
http://www.codemonkey.org.uk

Re: nokia 770 [was Re: community PM requirements/issues and PowerOP]

[Pavel Machek]

> >But what sense does it make for a user,sysadmin or 
> >application
> >to change voltage?  If any of these want to save power, 
> >they do so
> >by a) doing less work, and then b) lowering the clock 
> >speed as this
> >is inherently tied to voltage.
> 
> It makes sense to perform changing an operating point 
> dynamically in
> userland.

In very special cases, yes.

> That said, voltage should be accessible from userland.

Why?

If few states differ in voltage but not frequency, the only
user-visible thing is different latency of enter/exit.

If you only have two voltages per frequency (as it was shown in
examples here)... just add 1Hz to make difference between the two.

...but I guess you should teach cpufreq's ondemand governor to deal
with different latencies for different voltages. Before that is done
and shown to have significant power-saving impact, userspace interface
debate is useless.
							Pavel

-- 
Thanks for all the (sleeping) penguins.

Re: nokia 770 [was Re: community PM requirements/issues and PowerOP]

[Dmitry Krivoschekov]

Dave Jones wrote:

>On Thu, Dec 14, 2006 at 01:14:13PM +0300, Dmitry Krivoschekov wrote:
>
> > > > Ok, let's reword my sentence.  The cpufreq interface does not support  
> > > > voltage as a  parameter
> > >
> > >Please explain why this is useful at all.
> > >Under what circumstance is "Set the CPU voltage to 1.2V" a useful thing
> > >for a user, sysadmin, or application to do ?
> > >  
> > >
> > Voltage scaling is a well known technique to reduce power consumption, try
> > google search "Dynamic voltage scaling" if you are intrested in it.
>
>You've missed the point.  I'm well aware of dynamic voltage scaling,
>and some of the cpufreq drivers I've written do this.
>  
>
I'm sorry, I didn't want to offend you, just to be sure we are talking 
about
the same things.

> > I agree, in most cases we don't need to scale CPU voltage and frequency
> > independently since CPU frequency usually coupled with appropriate voltage
> > to set.
>
>A CPU frequency _always_ has a specific voltage associated with it.
>
>  
>
I have to correct you: "CPU frequency of x86 CPU's always has a specific
voltage", it is because of CPU designers have defined this voltage as
the best (or optimal maybe) voltage for this given frequency, it doesn't
mean CPU won't work on some different voltage, you just can say the CPU
with probability of say 99.9% will work stable on this voltage, but if you
want to rise performance you could do it via rising of voltage for example.

But, nobody says "let's give desktop user's the ability to control whatever
they may control, of course, it is dangerous to let an average desktop
user to do such things. But, think about designer who build embedded
mobile system that powered by Linux. Any mobile system always needs for
fine grained power management but you won't be able to tune an optimal
power consumption if you operate by only one parameter (cpufreq).


> > But some CPU's permit to choose frequency value for
> > a given voltage or vice versa
>
>But what sense does it make for a user,sysadmin or application
>to change voltage?  If any of these want to save power, they do so
>by a) doing less work, and then b) lowering the clock speed as this
>is inherently tied to voltage.
>
>  
>
You always think about this triage user,sysadmin and application of PC's,
think about embedded devices please, there we don't have stupid users
that want to on/off everthing. Why don't let a qualified engineer to tune
a number of parameters to get an optimal performance/power tradeoff?

>And if you lower voltage, you *MUST* reduce the frequency anyway.
>Running CPUs at higher speeds at lower voltages than those frequencies
>are rated for is a fastpath to a crash.
>  
>
I don't think it's always true, simply CMOS circuity won't work on voltage
levels below some limit.

>This is one fundamental reason I'm opposed to exporting voltages to userspace.
>Because people _will_ get this wrong, and we will see all manner of
>strange bugs and crashes reported from people running CPUs at higher
>speeds than the voltage is rated for.
>
>By putting this into the hands of userspace, we're setting ourselves up
>to fail.  How does userspace/users know what voltage is safe for what frequency?
>Without being intimate with the CPU datasheets, they're almost guaranteed
>to fail.  
>
Here I encourage to think about other users (system designers I mean)
who definetely have to read datasheets and other related docs.

>The _driver_ needs to know the pairings of voltage/frequency
>and export the only thing that makes sense.
>
> > Also, CPU is not the only power consumer in the system, you may need to 
> > scale voltage for other devices to get a best perfomance/power trade off.
> > And here is an obvious limitation of cpufreq since it takes care only
> > about CPU.
>
>You see it as a limitation, I see it behaving 'as designed'.
>If those devices have nothing to do with the CPU, why are they even
>relevant to this discussion?
>  
>
Because the discussion is related to PowerOP, and PowerOP in turn is
a set of different power parameters (or maybe not only power,
it's not a limitation).

>The argument seems to be "cpufreq only cares about CPU frequency, therefore
>we need something different".  But, why?  
>
Because a number of platforms permit to tune more parameters than CPU freq,
that in turn lets people to design more powersave systems, but cpufreq 
interface
restricts this ability.

But, I didn't ever say we need to remove cpufreq, I say we need to think not
only about PC's but also about embedded (mobile) systems that requre 
some different
solution.

Regards,
Dmitry

>I see no reason why we need
>to change cpufreq at all, just add additional interfaces to cover those
>other devices, as they're unrelated anyway.   And if there *are* any
>devices that are related, they can be tied into the existing cpufreq
>drivers just as for eg, the sa1100 drivers scale DRAM timings with CPU speed.
>
>		Dave
>
>  
>

Re: cpufreq terminally broken [was Re: community PM requirements/issues and PowerOP]

[David Brownell]

Catching up on some ancient mail from one mbox ..


On Wednesday 13 September 2006 4:50 pm, David Singleton wrote:
> OpPoint constructs operating points for all supported frequency, voltage
> and suspend states for PC and SoC solutions running Linux.

That's one basic issue I have with such approaches to desribing operating
points:  "all" such states gets to be an enormous set.  What I've seen of
both PowerOP and OpPoint says that they both try to limit that set by just
enumerating a handful of specific operating points ... but the more generic
solution (generally matching chip specs) would be having a way to constrain
the parameters within their natural limits.  (Rather than picking out a set
of half a dozen system modes in advance, by hand.)

 - With CPU clock at AAA MHz, chip voltage K must be between A1 and A2 volts;
   but those other clocks only need to follow their usual rules.   This
   defines a set of many operating points.

 - The MMC driver needs to have power supply P output 3.3 V at 80 mA and
   have clock D active.  (Presumably, a different set of operating points.)

 - If clock D is active, the SOC chip can't enter power state X; but again,
   other clocks can use their normal rules.  Again, many operating points.

 - While UART U3 is set to 115200 baud, certain values of clock M aren't
   allowed; but there are no other constraints, so that many operating
   points are compatible with that configuration.

 - Those chips must be in power state X for that module to enter power
   state Y; other modules can be in any power state.

 - That module must be in power state Y for the system to enter power
   state Z.

 - Because of chip errata, <these> parameter combinations (or transitions)
   are invalid; don't trigger them.

Cataloguing every possible power-related parameter seems like a losing
game, even on relatively tiny systems which pay attention to power usage
from within each driver ... and doomed to failure in larger scenarios,
like that 256-core case.

It seems that I'm actually criticizing the notion of "operating point" as
a model to expose as a power management target ...

It's simple to say that the system is at a particular operating point,
and that it's an operating point that works well for MP4 playback.  That's
like saying "it's warm today"; there are many kinds of warm day.  It's
purely descriptive, and omits lots of relevant details.  (Rainy too?)

But I really can't think it would be common for that to be the _only_ such
operating point ... simple counter-examples include the MMC and UART cases
above, considering that playback could often work with or without MMC active,
with or without UART at 115200 baud.  Ergo, multiple operating points support
MP4 playback, ergo "operating point" isn't the key notion that would need to
be exposed.  QED.

Now, where does that leave us?  I think it leaves us looking at how those
constraints get expressed (by e.g. device drivers for clocks and voltages,
ditto cpufreq drivers) and to what they get expressed (clock framework,
voltage framework, maybe a CPU horsepower manager the scheduler talks to).

So for that MP4 example, one could alert the video driver to do its clock
setup, a horsepower manager to say "intensive software decode load coming
up for this RT task", and one of the relevant operating points would be
entered.  And if the video data were coming from the MMC card, a slightly
different one would be entered as part of starting that data stream; etc.

Or in the 256-cpu example, just alert the horsepower manager that a huge
simulation job is upcoming ... that is, if the scheduler doesn't just do
that automatically when it notices it'd be a nice time to bring up some
of those currently-downed cores.  (Automatic up/down of cores may not
behave well in all cases.  By analogy:  madvise gives VM advice that can't
be guessed by the kernel; schedulers may need similar advice.)

Comments?

- Dave

Re: cpufreq terminally broken [was Re: community PM requirements/issues and PowerOP]

[Matthew Locke]

On Feb 27, 2007, at 12:55 PM, David Brownell wrote:

> Catching up on some ancient mail from one mbox ..
>
>
> On Wednesday 13 September 2006 4:50 pm, David Singleton wrote:
>> OpPoint constructs operating points for all supported frequency,  
>> voltage
>> and suspend states for PC and SoC solutions running Linux.
>
> That's one basic issue I have with such approaches to desribing  
> operating
> points:  "all" such states gets to be an enormous set.  What I've  
> seen of
> both PowerOP and OpPoint says that they both try to limit that set  
> by just
> enumerating a handful of specific operating points ... but the more  
> generic
> solution (generally matching chip specs) would be having a way to  
> constrain
> the parameters within their natural limits.  (Rather than picking  
> out a set
> of half a dozen system modes in advance, by hand.)

Agreed, well mostly anyway:)   Eugeny and I went back to the drawing  
board to see what we could do based on the comments last year and  
specifically Dominiks "Alternative concept" email.   Basically, we  
agree that the operating point notion is too limiting and artificial  
to be the basis for a power management stack.  Something like the  
knob layer described in Dominik's email is needed.   We have done a  
bit of thinking on the necessary behavior and features of such a layer.

  It's funny I was in the middle of writing up our thoughts in an  
email to the pm list when your email came in.  I will finish up that  
email and then come back to your specific examples below.

>
>  - With CPU clock at AAA MHz, chip voltage K must be between A1 and  
> A2 volts;
>    but those other clocks only need to follow their usual rules.    
> This
>    defines a set of many operating points.
>
>  - The MMC driver needs to have power supply P output 3.3 V at 80  
> mA and
>    have clock D active.  (Presumably, a different set of operating  
> points.)
>
>  - If clock D is active, the SOC chip can't enter power state X;  
> but again,
>    other clocks can use their normal rules.  Again, many operating  
> points.
>
>  - While UART U3 is set to 115200 baud, certain values of clock M  
> aren't
>    allowed; but there are no other constraints, so that many operating
>    points are compatible with that configuration.
>
>  - Those chips must be in power state X for that module to enter power
>    state Y; other modules can be in any power state.
>
>  - That module must be in power state Y for the system to enter power
>    state Z.
>
>  - Because of chip errata, <these> parameter combinations (or  
> transitions)
>    are invalid; don't trigger them.
>
> Cataloguing every possible power-related parameter seems like a losing
> game, even on relatively tiny systems which pay attention to power  
> usage
> from within each driver ... and doomed to failure in larger scenarios,
> like that 256-core case.
>
> It seems that I'm actually criticizing the notion of "operating  
> point" as
> a model to expose as a power management target ...
>
> It's simple to say that the system is at a particular operating point,
> and that it's an operating point that works well for MP4 playback.   
> That's
> like saying "it's warm today"; there are many kinds of warm day.  It's
> purely descriptive, and omits lots of relevant details.  (Rainy too?)
>
> But I really can't think it would be common for that to be the  
> _only_ such
> operating point ... simple counter-examples include the MMC and  
> UART cases
> above, considering that playback could often work with or without  
> MMC active,
> with or without UART at 115200 baud.  Ergo, multiple operating  
> points support
> MP4 playback, ergo "operating point" isn't the key notion that  
> would need to
> be exposed.  QED.
>
> Now, where does that leave us?  I think it leaves us looking at how  
> those
> constraints get expressed (by e.g. device drivers for clocks and  
> voltages,
> ditto cpufreq drivers) and to what they get expressed (clock  
> framework,
> voltage framework, maybe a CPU horsepower manager the scheduler  
> talks to).
>
> So for that MP4 example, one could alert the video driver to do its  
> clock
> setup, a horsepower manager to say "intensive software decode load  
> coming
> up for this RT task", and one of the relevant operating points  
> would be
> entered.  And if the video data were coming from the MMC card, a  
> slightly
> different one would be entered as part of starting that data  
> stream; etc.
>
> Or in the 256-cpu example, just alert the horsepower manager that a  
> huge
> simulation job is upcoming ... that is, if the scheduler doesn't  
> just do
> that automatically when it notices it'd be a nice time to bring up  
> some
> of those currently-downed cores.  (Automatic up/down of cores may not
> behave well in all cases.  By analogy:  madvise gives VM advice  
> that can't
> be guessed by the kernel; schedulers may need similar advice.)
>
> Comments?
>
> - Dave
>
>
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