[ath9k-devel] Power consumption questions

[ath9k-devel] Power consumption questions

[Harsha Chenji]

Hello all,

Thanks for the previous support on getting AP mode PSM to work. I now
have a few questions regarding the actual power consumption:

1. Will an AP in PSM mode see a decrease in current when it goes to
sleep? If so, does it need to be specifically enabled in
ath9k/mac80211/nl80211?

2. Will a device in IBSS mode with PSM turned on be able to see a
decrease in current?

I have tried both the above while observing current on a scope, but I
could not see any decrease. Is this normal?

Thanks,
Harsha

[ath9k-devel] Power consumption questions

[Adrian Chadd]

Hi!

There's two kinds of "power saving". People get them confused.

One is putting the NIC to sleep.

One is buffering packets, handling sleep/null qos data frames,
correctly setting TIM, etc. That way a station which is doing power
saving (ie, putting the NIC to sleep periodically) doesn't miss out on
packets destined to it.


Adrian

On 19 August 2011 06:05, Harsha Chenji <cjkernel@gmail.com> wrote:
> Hello all,
>
> Thanks for the previous support on getting AP mode PSM to work. I now
> have a few questions regarding the actual power consumption:
>
> 1. Will an AP in PSM mode see a decrease in current when it goes to
> sleep? If so, does it need to be specifically enabled in
> ath9k/mac80211/nl80211?
>
> 2. Will a device in IBSS mode with PSM turned on be able to see a
> decrease in current?
>
> I have tried both the above while observing current on a scope, but I
> could not see any decrease. Is this normal?
>
> Thanks,
> Harsha
> _______________________________________________
> ath9k-devel mailing list
> ath9k-devel at lists.ath9k.org
> https://lists.ath9k.org/mailman/listinfo/ath9k-devel
>

[ath9k-devel] Power consumption questions

[Harsha Chenji]

Hello Adrian,

My question was whether a NIC in AP/IBSS mode can be put to sleep,
reducing the current. After tracing through the code, I see that
CONFIG_PM first needs to be enabled for pci based power management
(does ath9k use this or does it switch itself off?). In
mac80211/iface.c, it looks like if there any monitor mode or AP mode
interfaces active, the NIC will not be put to sleep
(http://osdir.com/ml/linux-wireless/2009-04/msg01158.html).

Now the standards do provide for IBSS STAs to enter a Doze state - but
I do not observe this in ath9k. Where should I look to enable this?
Does the hardware do it by itself or does it need mac80211 to do it?

Thanks

On Thu, Aug 18, 2011 at 8:12 PM, Adrian Chadd <adrian@freebsd.org> wrote:
> Hi!
>
> There's two kinds of "power saving". People get them confused.
>
> One is putting the NIC to sleep.
>
> One is buffering packets, handling sleep/null qos data frames,
> correctly setting TIM, etc. That way a station which is doing power
> saving (ie, putting the NIC to sleep periodically) doesn't miss out on
> packets destined to it.
>
>
> Adrian
>
> On 19 August 2011 06:05, Harsha Chenji <cjkernel@gmail.com> wrote:
>> Hello all,
>>
>> Thanks for the previous support on getting AP mode PSM to work. I now
>> have a few questions regarding the actual power consumption:
>>
>> 1. Will an AP in PSM mode see a decrease in current when it goes to
>> sleep? If so, does it need to be specifically enabled in
>> ath9k/mac80211/nl80211?
>>
>> 2. Will a device in IBSS mode with PSM turned on be able to see a
>> decrease in current?
>>
>> I have tried both the above while observing current on a scope, but I
>> could not see any decrease. Is this normal?
>>
>> Thanks,
>> Harsha
>> _______________________________________________
>> ath9k-devel mailing list
>> ath9k-devel at lists.ath9k.org
>> https://lists.ath9k.org/mailman/listinfo/ath9k-devel
>>
>

[ath9k-devel] Power consumption questions

[Adrian Chadd]

Hm, you're going to need to research and implement ATIM support, if
it's not in there already.
The hardware supports it and I think the driver has part of what you
need to support it (it has the auto-wake timer stuff for AR9280 and
later, I think.)
Yes, I think you're going to have to code up some stuff, both in
mac80211 and the driver. But I'm not clued up on what mac80211, etc
supports just at the moment (I'm more focused on the driver side of
things.)

If you'd like to take a crack at getting the NIC to sleep and wake up
for IBSS, I'm sure I and others can help you wade through the murky
waters of ath9k power saving. :-)



adrian

On 19 August 2011 10:11, Harsha Chenji <cjkernel@gmail.com> wrote:
> Hello Adrian,
>
> My question was whether a NIC in AP/IBSS mode can be put to sleep,
> reducing the current. After tracing through the code, I see that
> CONFIG_PM first needs to be enabled for pci based power management
> (does ath9k use this or does it switch itself off?). In
> mac80211/iface.c, it looks like if there any monitor mode or AP mode
> interfaces active, the NIC will not be put to sleep
> (http://osdir.com/ml/linux-wireless/2009-04/msg01158.html).
>
> Now the standards do provide for IBSS STAs to enter a Doze state - but
> I do not observe this in ath9k. Where should I look to enable this?
> Does the hardware do it by itself or does it need mac80211 to do it?
>
> Thanks
>
> On Thu, Aug 18, 2011 at 8:12 PM, Adrian Chadd <adrian@freebsd.org> wrote:
>> Hi!
>>
>> There's two kinds of "power saving". People get them confused.
>>
>> One is putting the NIC to sleep.
>>
>> One is buffering packets, handling sleep/null qos data frames,
>> correctly setting TIM, etc. That way a station which is doing power
>> saving (ie, putting the NIC to sleep periodically) doesn't miss out on
>> packets destined to it.
>>
>>
>> Adrian
>>
>> On 19 August 2011 06:05, Harsha Chenji <cjkernel@gmail.com> wrote:
>>> Hello all,
>>>
>>> Thanks for the previous support on getting AP mode PSM to work. I now
>>> have a few questions regarding the actual power consumption:
>>>
>>> 1. Will an AP in PSM mode see a decrease in current when it goes to
>>> sleep? If so, does it need to be specifically enabled in
>>> ath9k/mac80211/nl80211?
>>>
>>> 2. Will a device in IBSS mode with PSM turned on be able to see a
>>> decrease in current?
>>>
>>> I have tried both the above while observing current on a scope, but I
>>> could not see any decrease. Is this normal?
>>>
>>> Thanks,
>>> Harsha
>>> _______________________________________________
>>> ath9k-devel mailing list
>>> ath9k-devel at lists.ath9k.org
>>> https://lists.ath9k.org/mailman/listinfo/ath9k-devel
>>>
>>
>

[ath9k-devel] Power consumption questions

[Harsha Chenji]

Sure, I will need all the help I guess. But since I have a deadline in September, I will start working on this once I get other things finished up. I did look in ibss.c, it looks like there is no ATIM idling support.

Thanks for the help
 
On Aug 18, 2011, at 11:52 PM, Adrian Chadd wrote:

> Hm, you're going to need to research and implement ATIM support, if
> it's not in there already.
> The hardware supports it and I think the driver has part of what you
> need to support it (it has the auto-wake timer stuff for AR9280 and
> later, I think.)
> Yes, I think you're going to have to code up some stuff, both in
> mac80211 and the driver. But I'm not clued up on what mac80211, etc
> supports just at the moment (I'm more focused on the driver side of
> things.)
> 
> If you'd like to take a crack at getting the NIC to sleep and wake up
> for IBSS, I'm sure I and others can help you wade through the murky
> waters of ath9k power saving. :-)
> 
> 
> 
> adrian
> 
> On 19 August 2011 10:11, Harsha Chenji <cjkernel@gmail.com> wrote:
>> Hello Adrian,
>> 
>> My question was whether a NIC in AP/IBSS mode can be put to sleep,
>> reducing the current. After tracing through the code, I see that
>> CONFIG_PM first needs to be enabled for pci based power management
>> (does ath9k use this or does it switch itself off?). In
>> mac80211/iface.c, it looks like if there any monitor mode or AP mode
>> interfaces active, the NIC will not be put to sleep
>> (http://osdir.com/ml/linux-wireless/2009-04/msg01158.html).
>> 
>> Now the standards do provide for IBSS STAs to enter a Doze state - but
>> I do not observe this in ath9k. Where should I look to enable this?
>> Does the hardware do it by itself or does it need mac80211 to do it?
>> 
>> Thanks
>> 
>> On Thu, Aug 18, 2011 at 8:12 PM, Adrian Chadd <adrian@freebsd.org> wrote:
>>> Hi!
>>> 
>>> There's two kinds of "power saving". People get them confused.
>>> 
>>> One is putting the NIC to sleep.
>>> 
>>> One is buffering packets, handling sleep/null qos data frames,
>>> correctly setting TIM, etc. That way a station which is doing power
>>> saving (ie, putting the NIC to sleep periodically) doesn't miss out on
>>> packets destined to it.
>>> 
>>> 
>>> Adrian
>>> 
>>> On 19 August 2011 06:05, Harsha Chenji <cjkernel@gmail.com> wrote:
>>>> Hello all,
>>>> 
>>>> Thanks for the previous support on getting AP mode PSM to work. I now
>>>> have a few questions regarding the actual power consumption:
>>>> 
>>>> 1. Will an AP in PSM mode see a decrease in current when it goes to
>>>> sleep? If so, does it need to be specifically enabled in
>>>> ath9k/mac80211/nl80211?
>>>> 
>>>> 2. Will a device in IBSS mode with PSM turned on be able to see a
>>>> decrease in current?
>>>> 
>>>> I have tried both the above while observing current on a scope, but I
>>>> could not see any decrease. Is this normal?
>>>> 
>>>> Thanks,
>>>> Harsha
>>>> _______________________________________________
>>>> ath9k-devel mailing list
>>>> ath9k-devel at lists.ath9k.org
>>>> https://lists.ath9k.org/mailman/listinfo/ath9k-devel
>>>> 
>>> 
>>