Server Power On mystery

Server Power On mystery

[Mike Jones]

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Hi,

I am trying to understand how the Server power button in the webui works.

As before, using raspberry pi, and I’ll leave project links at the end for anyone that wants to use them. Things work up to monitoring voltages. Note the conf project has a phosphor branch for the full monty.

To reverse engineer, I setup: dbus-monitor —system > someFile.log

There is a message for systemd1.Manager; member=StartUnit and best I can tell, somehow this gets routed to systemd to start some service or run some exe. I see this mentioned in the dbus transactions:

"obmc-host-start@0.target <mailto:obmc-host-start@0.target>”

And that is in /lib/systemd/system and depends on obmc-host-startmin@0.target, but that does not depend on any service. So that is a dead end. It also depends on a reboot attempts, but I think that is not responsible for power on/off.

Then there are chassis services, but I cannot find a link from obmc-host-start@0.target to objc-chassis-poweron@0.target.

In this doc: https://github.com/openbmc/docs/blob/master/architecture/openbmc-systemd.md <https://github.com/openbmc/docs/blob/master/architecture/openbmc-systemd.md>

It shows:


ls -1 /lib/systemd/system/obmc-chassis-poweron\@0.target.requires/
op-power-start@0.service
op-wait-power-on@0.service

But when I “ls” that path, the above dependencies are not there. There is only a dependency on phosphor-fan-presence-tach@0.service <mailto:phosphor-fan-presence-tach@0.service>

There is some state service that lead to things with xzy paths, and I eventually found /run/systemd/units. These have file names starting with “invocation” in the names and link to GUID like nodes that don’t “cat” like a normal file. So I am not sure how those work. Is there some kernel driver that works like sysfs so that these nodes are not traditional files?

What I am trying to understand is two things:

- Interaction with the power regulator
- Interaction with the host cpu

So my hope is someone can connect the dots of the path from the dbus to systemd through the targets to a service executable doing the work so I can try to replace them with:

- Something that turns the regulators on/off, with pmbus in this case.
- Something that can behave like a host to keep the system happy like a real system.

Mike

My repos
——————

https://github.com/Proclivis/meta-pmbus-raspberrypi.git <https://github.com/Proclivis/meta-pmbus-raspberrypi.git>
https://github.com/Proclivis/meta-pmbus-phosphor.git <https://github.com/Proclivis/meta-pmbus-phosphor.git>
https://github.com/Proclivis/conf-openbmc-adi.git <https://github.com/Proclivis/conf-openbmc-adi.git>

The monitor messages for StartUnit
———

method call time=1598039669.247458 sender=:1.48 -> destination=org.freedesktop.systemd1 serial=33 path=/org/freedesktop/systemd1; interface=org.freedesktop.systemd1.Manager; member=StartUnit
   string "obmc-host-start@0.target <mailto:obmc-host-start@0.target>"
   string "replace"
method call time=1598039669.276170 sender=:1.3 -> destination=org.freedesktop.DBus serial=775 path=/org/freedesktop/DBus; interface=org.freedesktop.DBus; member=GetConnectionUnixUser
   string ":1.48"
method return time=1598039669.276234 sender=org.freedesktop.DBus -> destination=:1.3 serial=4294967295 reply_serial=775
   uint32 0
method call time=1598039669.280376 sender=:1.3 -> destination=org.freedesktop.DBus serial=776 path=/org/freedesktop/DBus; interface=org.freedesktop.DBus; member=AddMatch
   string "type='signal',sender='org.freedesktop.DBus',path='/org/freedesktop/DBus',interface='org.freedesktop.DBus',member='NameOwnerChanged',arg0=':1.48'"
method return time=1598039669.280661 sender=org.freedesktop.DBus -> destination=:1.3 serial=4294967295 reply_serial=776
method call time=1598039669.280701 sender=:1.3 -> destination=org.freedesktop.DBus serial=777 path=/org/freedesktop/DBus; interface=org.freedesktop.DBus; member=GetNameOwner
   string ":1.48"
method return time=1598039669.280738 sender=org.freedesktop.DBus -> destination=:1.3 serial=4294967295 reply_serial=777
   string ":1.48"
signal time=1598039669.280774 sender=:1.3 -> destination=(null destination) serial=778 path=/org/freedesktop/systemd1; interface=org.freedesktop.systemd1.Manager; member=UnitNew
   string "obmc-host-start@0.target <mailto:obmc-host-start@0.target>"
   object path "/org/freedesktop/systemd1/unit/obmc_2dhost_2dstart_400_2etarget"
signal time=1598039669.280823 sender=:1.3 -> destination=(null destination) serial=779 path=/org/freedesktop/systemd1; interface=org.freedesktop.systemd1.Manager; member=JobNew
   uint32 1105
   object path "/org/freedesktop/systemd1/job/1105"
   string "obmc-host-start@0.target <mailto:obmc-host-start@0.target>"
method return time=1598039669.280883 sender=:1.3 -> destination=:1.48 serial=780 reply_serial=33
   object path "/org/freedesktop/systemd1/job/1105"
signal time=1598039669.281305 sender=:1.48 -> destination=(null destination) serial=34 path=/xyz/openbmc_project/state/host0; interface=org.freedesktop.DBus.Properties; member=PropertiesChanged
   string "xyz.openbmc_project.State.Host"
   array [
      dict entry(
         string "RequestedHostTransition"
         variant             string "xyz.openbmc_project.State.Host.Transition.On"
      )
   ]
   array [
   ]

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Re: Server Power On mystery

[Milton Miller II]

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Re: Server Power On mystery

[Milton Miller II]

Resend as plain text.

>On August 21, 2020, Mike Jones wrote:>I am trying to understand how
>the Server power button in the webui
>>works.
>>
>>As before, using raspberry pi, and I’ll leave project links at the
>>end for anyone that wants to use them. Things work up to monitoring
>>voltages. Note the conf project has a phosphor branch for the full
>>monty.>>To reverse engineer, I setup: dbus-monitor —system >
>someFile.log
>>
>>There is a message for systemd1.Manager; member=StartUnit and best I
>>can tell, somehow this gets routed to systemd to start some service
>>or run some exe. I see this mentioned in the dbus transactions:
>>
>>"obmc-host-start@0.target”
>>
>>And that is in /lib/systemd/system and depends
>>on obmc-host-startmin@0.target, but that does not depend on any
>>service. So that is a dead end. It also depends on a reboot
>attempts,
>>but I think that is not responsible for power on/off.
>>
>>Then there are chassis services, but I cannot find a link from
>>obmc-host-start@0.target to objc-chassis-poweron@0.target.
>
>
>
>>>In this
>>doc: https://github.com/openbmc/docs/blob/master/architecture/openbm
>c
>>-systemd.md
>>
>>It shows:
>>
>>
>>ls -1 /lib/systemd/system/obmc-chassis-poweron\@0.target.requires/
>>op-power-start@0.service op-wait-power-on@0.service>>But when I “ls”
>that path, the above dependencies are not there.
>>There is only a dependency on phosphor-fan-presence-tach@0.service
>>
>>There is some state service that lead to things with xzy paths, and
>I
>>eventually found /run/systemd/units. These have file names starting
>>with “invocation” in the names and link to GUID like nodes that
>don’t
>>“cat” like a normal file. So I am not sure how those work. Is there
>>some kernel driver that works like sysfs so that these nodes are not
>>traditional files?
>>
>>What I am trying to understand is two things:
>>
>>- Interaction with the power regulator
>>- Interaction with the host cpu
>>
>>So my hope is someone can connect the dots of the path from the dbus
>>to systemd through the targets to a service executable doing the
>work
>>so I can try to replace them with:
>>
>>- Something that turns the regulators on/off, with pmbus in this
>>case.
>>- Something that can behave like a host to keep the system happy
>like
>>a real system.
>
>
>
>Hi.  There is some design documentation here
>
>https://github.com/openbmc/docs/blob/master/designs/state-management-
>and-external-interfaces.md
>
>and that links to phosphor-state-manager which has a lot of the units
>
>that kick off power and state transitions.
>
>
>The op-power-start are for systems following the OpenPOWER reference 
>designs.  The regulators are sequenced by an external microcontroller
>
>based on the state of a POWER_ON gpio from the BMC and a return 
>PGOOD to indicate the state.  There are also other op- prefixed units
>that 
>initiate the host processor initialization (after the units check
>that fans are 
>running as you found).  
>
>There is also a watchdog that is started when the host is started and
>
>pinged and stopped via IPMI.
>
>If you are prototyping for a x86 system, there are alternative 
>power implementations where the gpio toggles to represent a 
>main power button push and their start cpu sequences.  I think 
>there are also arm systems but don't know what they are using 
>for host interaction.
>
>I hope this advances your investigation and learning.
>
>milton
>
>>>Mike
>>
>>My repos
>>——————
>>
>>https://github.com/Proclivis/meta-pmbus-raspberrypi.git
>>https://github.com/Proclivis/meta-pmbus-phosphor.git
>>https://github.com/Proclivis/conf-openbmc-adi.git
>>
>>The monitor messages for StartUnit
>>———
>>
>>method call time=1598039669.247458 sender=:1.48 ->
>>destination=org.freedesktop.systemd1 serial=33
>>path=/org/freedesktop/systemd1;
>>interface=org.freedesktop.systemd1.Manager; member=StartUnit
>>   string "obmc-host-start@0.target"
>>   string "replace"
>>method call time=1598039669.276170 sender=:1.3 ->
>>destination=org.freedesktop.DBus serial=775
>>path=/org/freedesktop/DBus; interface=org.freedesktop.DBus;
>>member=GetConnectionUnixUser
>>   string ":1.48"
>>method return time=1598039669.276234 sender=org.freedesktop.DBus ->
>>destination=:1.3 serial=4294967295 reply_serial=775
>>   uint32 0
>>method call time=1598039669.280376 sender=:1.3 ->
>>destination=org.freedesktop.DBus serial=776
>>path=/org/freedesktop/DBus; interface=org.freedesktop.DBus;
>>member=AddMatch
>>   string
>>"type='signal',sender='org.freedesktop.DBus',path='/org/freedesktop/
>D
>>Bus',interface='org.freedesktop.DBus',member='NameOwnerChanged',arg0
>=
>>':1.48'"
>>method return time=1598039669.280661 sender=org.freedesktop.DBus ->
>>destination=:1.3 serial=4294967295 reply_serial=776
>>method call time=1598039669.280701 sender=:1.3 ->
>>destination=org.freedesktop.DBus serial=777
>>path=/org/freedesktop/DBus; interface=org.freedesktop.DBus;
>>member=GetNameOwner
>>   string ":1.48"
>>method return time=1598039669.280738 sender=org.freedesktop.DBus ->
>>destination=:1.3 serial=4294967295 reply_serial=777
>>   string ":1.48"
>>signal time=1598039669.280774 sender=:1.3 -> destination=(null
>>destination) serial=778 path=/org/freedesktop/systemd1;
>>interface=org.freedesktop.systemd1.Manager; member=UnitNew
>>   string "obmc-host-start@0.target"
>>   object path
>>"/org/freedesktop/systemd1/unit/obmc_2dhost_2dstart_400_2etarget"
>>signal time=1598039669.280823 sender=:1.3 -> destination=(null
>>destination) serial=779 path=/org/freedesktop/systemd1;
>>interface=org.freedesktop.systemd1.Manager; member=JobNew
>>   uint32 1105
>>   object path "/org/freedesktop/systemd1/job/1105"
>>   string "obmc-host-start@0.target"
>>method return time=1598039669.280883 sender=:1.3 ->
>destination=:1.48
>>serial=780 reply_serial=33
>>   object path "/org/freedesktop/systemd1/job/1105"
>>signal time=1598039669.281305 sender=:1.48 -> destination=(null
>>destination) serial=34 path=/xyz/openbmc_project/state/host0;
>>interface=org.freedesktop.DBus.Properties; member=PropertiesChanged
>>   string "xyz.openbmc_project.State.Host"
>>   array [
>>      dict entry(
>>         string "RequestedHostTransition"
>>         variant             string
>>"xyz.openbmc_project.State.Host.Transition.On"
>>      )
>>   ]
>>   array [
>>   ]

Re: Server Power On mystery

[Mike Jones]

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Milton,

This is giving me a good start and I am digging through the docs.

I want to test my concepts, so for each of these, I’ll write what I think is true and you can tell me where I am wrong, and put a question where I am not sure.

- BMC power is assumed to be independent from BMC power
- Enabling chassis power can interact with a HotSwap device or power path switching device, or an IBC, etc, to power on/off everything in the chassis but the BMC
- When the Host is off, does this imply it has no power, or that the host is in an idle state and not running but has power applied?
- For the above question, I assume most systems are VRM based
- What about auxiliary supplies? Suppose a design has an FPGA or DSP independent from the host. Are these expected to follow chassis or host power? In non-CPU systems, the poweron of an FPGA and other support chips can have a complicated sequence. Is that handled in an integrated fashion with the VRM or independently?

Mike

> On Aug 23, 2020, at 9:22 PM, Milton Miller II <miltonm@us.ibm.com> wrote:
> 
> Resend as plain text.
> 
>> On August 21, 2020, Mike Jones wrote:>I am trying to understand how
>> the Server power button in the webui
>>> works.
>>> 
>>> As before, using raspberry pi, and I’ll leave project links at the
>>> end for anyone that wants to use them. Things work up to monitoring
>>> voltages. Note the conf project has a phosphor branch for the full
>>> monty.>>To reverse engineer, I setup: dbus-monitor —system >
>> someFile.log
>>> 
>>> There is a message for systemd1.Manager; member=StartUnit and best I
>>> can tell, somehow this gets routed to systemd to start some service
>>> or run some exe. I see this mentioned in the dbus transactions:
>>> 
>>> "obmc-host-start@0.target”
>>> 
>>> And that is in /lib/systemd/system and depends
>>> on obmc-host-startmin@0.target, but that does not depend on any
>>> service. So that is a dead end. It also depends on a reboot
>> attempts,
>>> but I think that is not responsible for power on/off.
>>> 
>>> Then there are chassis services, but I cannot find a link from
>>> obmc-host-start@0.target to objc-chassis-poweron@0.target.
>> 
>> 
>> 
>>>> In this
>>> doc: https://github.com/openbmc/docs/blob/master/architecture/openbm
>> c
>>> -systemd.md
>>> 
>>> It shows:
>>> 
>>> 
>>> ls -1 /lib/systemd/system/obmc-chassis-poweron\@0.target.requires/
>>> op-power-start@0.service op-wait-power-on@0.service>>But when I “ls”
>> that path, the above dependencies are not there.
>>> There is only a dependency on phosphor-fan-presence-tach@0.service
>>> 
>>> There is some state service that lead to things with xzy paths, and
>> I
>>> eventually found /run/systemd/units. These have file names starting
>>> with “invocation” in the names and link to GUID like nodes that
>> don’t
>>> “cat” like a normal file. So I am not sure how those work. Is there
>>> some kernel driver that works like sysfs so that these nodes are not
>>> traditional files?
>>> 
>>> What I am trying to understand is two things:
>>> 
>>> - Interaction with the power regulator
>>> - Interaction with the host cpu
>>> 
>>> So my hope is someone can connect the dots of the path from the dbus
>>> to systemd through the targets to a service executable doing the
>> work
>>> so I can try to replace them with:
>>> 
>>> - Something that turns the regulators on/off, with pmbus in this
>>> case.
>>> - Something that can behave like a host to keep the system happy
>> like
>>> a real system.
>> 
>> 
>> 
>> Hi.  There is some design documentation here
>> 
>> https://github.com/openbmc/docs/blob/master/designs/state-management- <https://github.com/openbmc/docs/blob/master/designs/state-management->
>> and-external-interfaces.md
>> 
>> and that links to phosphor-state-manager which has a lot of the units
>> 
>> that kick off power and state transitions.
>> 
>> 
>> The op-power-start are for systems following the OpenPOWER reference 
>> designs.  The regulators are sequenced by an external microcontroller
>> 
>> based on the state of a POWER_ON gpio from the BMC and a return 
>> PGOOD to indicate the state.  There are also other op- prefixed units
>> that 
>> initiate the host processor initialization (after the units check
>> that fans are 
>> running as you found).  
>> 
>> There is also a watchdog that is started when the host is started and
>> 
>> pinged and stopped via IPMI.
>> 
>> If you are prototyping for a x86 system, there are alternative 
>> power implementations where the gpio toggles to represent a 
>> main power button push and their start cpu sequences.  I think 
>> there are also arm systems but don't know what they are using 
>> for host interaction.
>> 
>> I hope this advances your investigation and learning.
>> 
>> milton
>> 
>>>> Mike
>>> 
>>> My repos
>>> ——————
>>> 
>>> https://github.com/Proclivis/meta-pmbus-raspberrypi.git
>>> https://github.com/Proclivis/meta-pmbus-phosphor.git
>>> https://github.com/Proclivis/conf-openbmc-adi.git
>>> 
>>> The monitor messages for StartUnit
>>> ———
>>> 
>>> method call time=1598039669.247458 sender=:1.48 ->
>>> destination=org.freedesktop.systemd1 serial=33
>>> path=/org/freedesktop/systemd1;
>>> interface=org.freedesktop.systemd1.Manager; member=StartUnit
>>>  string "obmc-host-start@0.target"
>>>  string "replace"
>>> method call time=1598039669.276170 sender=:1.3 ->
>>> destination=org.freedesktop.DBus serial=775
>>> path=/org/freedesktop/DBus; interface=org.freedesktop.DBus;
>>> member=GetConnectionUnixUser
>>>  string ":1.48"
>>> method return time=1598039669.276234 sender=org.freedesktop.DBus ->
>>> destination=:1.3 serial=4294967295 reply_serial=775
>>>  uint32 0
>>> method call time=1598039669.280376 sender=:1.3 ->
>>> destination=org.freedesktop.DBus serial=776
>>> path=/org/freedesktop/DBus; interface=org.freedesktop.DBus;
>>> member=AddMatch
>>>  string
>>> "type='signal',sender='org.freedesktop.DBus',path='/org/freedesktop/
>> D
>>> Bus',interface='org.freedesktop.DBus',member='NameOwnerChanged',arg0
>> =
>>> ':1.48'"
>>> method return time=1598039669.280661 sender=org.freedesktop.DBus ->
>>> destination=:1.3 serial=4294967295 reply_serial=776
>>> method call time=1598039669.280701 sender=:1.3 ->
>>> destination=org.freedesktop.DBus serial=777
>>> path=/org/freedesktop/DBus; interface=org.freedesktop.DBus;
>>> member=GetNameOwner
>>>  string ":1.48"
>>> method return time=1598039669.280738 sender=org.freedesktop.DBus ->
>>> destination=:1.3 serial=4294967295 reply_serial=777
>>>  string ":1.48"
>>> signal time=1598039669.280774 sender=:1.3 -> destination=(null
>>> destination) serial=778 path=/org/freedesktop/systemd1;
>>> interface=org.freedesktop.systemd1.Manager; member=UnitNew
>>>  string "obmc-host-start@0.target"
>>>  object path
>>> "/org/freedesktop/systemd1/unit/obmc_2dhost_2dstart_400_2etarget"
>>> signal time=1598039669.280823 sender=:1.3 -> destination=(null
>>> destination) serial=779 path=/org/freedesktop/systemd1;
>>> interface=org.freedesktop.systemd1.Manager; member=JobNew
>>>  uint32 1105
>>>  object path "/org/freedesktop/systemd1/job/1105"
>>>  string "obmc-host-start@0.target"
>>> method return time=1598039669.280883 sender=:1.3 ->
>> destination=:1.48
>>> serial=780 reply_serial=33
>>>  object path "/org/freedesktop/systemd1/job/1105"
>>> signal time=1598039669.281305 sender=:1.48 -> destination=(null
>>> destination) serial=34 path=/xyz/openbmc_project/state/host0;
>>> interface=org.freedesktop.DBus.Properties; member=PropertiesChanged
>>>  string "xyz.openbmc_project.State.Host"
>>>  array [
>>>     dict entry(
>>>        string "RequestedHostTransition"
>>>        variant             string
>>> "xyz.openbmc_project.State.Host.Transition.On"
>>>     )
>>>  ]
>>>  array [
>>>  ]


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Re: Server Power On mystery

[Ed Tanous]

I think the best thing would be to start off by stating exactly what
you're trying to accomplish, and we can go from there.  As is, you're
using a raspberry pi, which doesn't have a "host" in the normal BMC
sense, so I'm really confused as to what you're hoping to do with the
host power button.  Are you trying to reboot the raspberry pi?  Reboot
a host connected through some other means?

-Ed

On Fri, Aug 21, 2020 at 3:29 PM Mike Jones <proclivis@gmail.com> wrote:
>
> Hi,
>
> I am trying to understand how the Server power button in the webui works.
>
> As before, using raspberry pi, and I’ll leave project links at the end for anyone that wants to use them. Things work up to monitoring voltages. Note the conf project has a phosphor branch for the full monty.
>
> To reverse engineer, I setup: dbus-monitor —system > someFile.log
>
> There is a message for systemd1.Manager; member=StartUnit and best I can tell, somehow this gets routed to systemd to start some service or run some exe. I see this mentioned in the dbus transactions:
>
> "obmc-host-start@0.target”
>
> And that is in /lib/systemd/system and depends on obmc-host-startmin@0.target, but that does not depend on any service. So that is a dead end. It also depends on a reboot attempts, but I think that is not responsible for power on/off.
>
> Then there are chassis services, but I cannot find a link from obmc-host-start@0.target to objc-chassis-poweron@0.target.
>
> In this doc: https://github.com/openbmc/docs/blob/master/architecture/openbmc-systemd.md
>
> It shows:
>
>
> ls -1 /lib/systemd/system/obmc-chassis-poweron\@0.target.requires/
> op-power-start@0.service
> op-wait-power-on@0.service
>
>
> But when I “ls” that path, the above dependencies are not there. There is only a dependency on phosphor-fan-presence-tach@0.service
>
> There is some state service that lead to things with xzy paths, and I eventually found /run/systemd/units. These have file names starting with “invocation” in the names and link to GUID like nodes that don’t “cat” like a normal file. So I am not sure how those work. Is there some kernel driver that works like sysfs so that these nodes are not traditional files?
>
> What I am trying to understand is two things:
>
> - Interaction with the power regulator
> - Interaction with the host cpu
>
> So my hope is someone can connect the dots of the path from the dbus to systemd through the targets to a service executable doing the work so I can try to replace them with:
>
> - Something that turns the regulators on/off, with pmbus in this case.
> - Something that can behave like a host to keep the system happy like a real system.
>
> Mike
>
> My repos
> ——————
>
> https://github.com/Proclivis/meta-pmbus-raspberrypi.git
> https://github.com/Proclivis/meta-pmbus-phosphor.git
> https://github.com/Proclivis/conf-openbmc-adi.git
>
> The monitor messages for StartUnit
> ———
>
> method call time=1598039669.247458 sender=:1.48 -> destination=org.freedesktop.systemd1 serial=33 path=/org/freedesktop/systemd1; interface=org.freedesktop.systemd1.Manager; member=StartUnit
>    string "obmc-host-start@0.target"
>    string "replace"
> method call time=1598039669.276170 sender=:1.3 -> destination=org.freedesktop.DBus serial=775 path=/org/freedesktop/DBus; interface=org.freedesktop.DBus; member=GetConnectionUnixUser
>    string ":1.48"
> method return time=1598039669.276234 sender=org.freedesktop.DBus -> destination=:1.3 serial=4294967295 reply_serial=775
>    uint32 0
> method call time=1598039669.280376 sender=:1.3 -> destination=org.freedesktop.DBus serial=776 path=/org/freedesktop/DBus; interface=org.freedesktop.DBus; member=AddMatch
>    string "type='signal',sender='org.freedesktop.DBus',path='/org/freedesktop/DBus',interface='org.freedesktop.DBus',member='NameOwnerChanged',arg0=':1.48'"
> method return time=1598039669.280661 sender=org.freedesktop.DBus -> destination=:1.3 serial=4294967295 reply_serial=776
> method call time=1598039669.280701 sender=:1.3 -> destination=org.freedesktop.DBus serial=777 path=/org/freedesktop/DBus; interface=org.freedesktop.DBus; member=GetNameOwner
>    string ":1.48"
> method return time=1598039669.280738 sender=org.freedesktop.DBus -> destination=:1.3 serial=4294967295 reply_serial=777
>    string ":1.48"
> signal time=1598039669.280774 sender=:1.3 -> destination=(null destination) serial=778 path=/org/freedesktop/systemd1; interface=org.freedesktop.systemd1.Manager; member=UnitNew
>    string "obmc-host-start@0.target"
>    object path "/org/freedesktop/systemd1/unit/obmc_2dhost_2dstart_400_2etarget"
> signal time=1598039669.280823 sender=:1.3 -> destination=(null destination) serial=779 path=/org/freedesktop/systemd1; interface=org.freedesktop.systemd1.Manager; member=JobNew
>    uint32 1105
>    object path "/org/freedesktop/systemd1/job/1105"
>    string "obmc-host-start@0.target"
> method return time=1598039669.280883 sender=:1.3 -> destination=:1.48 serial=780 reply_serial=33
>    object path "/org/freedesktop/systemd1/job/1105"
> signal time=1598039669.281305 sender=:1.48 -> destination=(null destination) serial=34 path=/xyz/openbmc_project/state/host0; interface=org.freedesktop.DBus.Properties; member=PropertiesChanged
>    string "xyz.openbmc_project.State.Host"
>    array [
>       dict entry(
>          string "RequestedHostTransition"
>          variant             string "xyz.openbmc_project.State.Host.Transition.On"
>       )
>    ]
>    array [
>    ]

Re: Server Power On mystery

[Mike]

Ed,

My goals are atypical 

- Understand typical obmc use cases to see how various ADI devices would fit in: Hot Swap, Power Sequencers, PMBus regulators 
- Try these use cases in raspi by neutering or faking the host
- Create linux drivers to support obmc

Mike

Sent from my iPhone

> On Aug 24, 2020, at 12:41 PM, Ed Tanous <ed@tanous.net> wrote:
> 
> I think the best thing would be to start off by stating exactly what
> you're trying to accomplish, and we can go from there.  As is, you're
> using a raspberry pi, which doesn't have a "host" in the normal BMC
> sense, so I'm really confused as to what you're hoping to do with the
> host power button.  Are you trying to reboot the raspberry pi?  Reboot
> a host connected through some other means?
> 
> -Ed
> 
>> On Fri, Aug 21, 2020 at 3:29 PM Mike Jones <proclivis@gmail.com> wrote:
>> 
>> Hi,
>> 
>> I am trying to understand how the Server power button in the webui works.
>> 
>> As before, using raspberry pi, and I’ll leave project links at the end for anyone that wants to use them. Things work up to monitoring voltages. Note the conf project has a phosphor branch for the full monty.
>> 
>> To reverse engineer, I setup: dbus-monitor —system > someFile.log
>> 
>> There is a message for systemd1.Manager; member=StartUnit and best I can tell, somehow this gets routed to systemd to start some service or run some exe. I see this mentioned in the dbus transactions:
>> 
>> "obmc-host-start@0.target”
>> 
>> And that is in /lib/systemd/system and depends on obmc-host-startmin@0.target, but that does not depend on any service. So that is a dead end. It also depends on a reboot attempts, but I think that is not responsible for power on/off.
>> 
>> Then there are chassis services, but I cannot find a link from obmc-host-start@0.target to objc-chassis-poweron@0.target.
>> 
>> In this doc: https://github.com/openbmc/docs/blob/master/architecture/openbmc-systemd.md
>> 
>> It shows:
>> 
>> 
>> ls -1 /lib/systemd/system/obmc-chassis-poweron\@0.target.requires/
>> op-power-start@0.service
>> op-wait-power-on@0.service
>> 
>> 
>> But when I “ls” that path, the above dependencies are not there. There is only a dependency on phosphor-fan-presence-tach@0.service
>> 
>> There is some state service that lead to things with xzy paths, and I eventually found /run/systemd/units. These have file names starting with “invocation” in the names and link to GUID like nodes that don’t “cat” like a normal file. So I am not sure how those work. Is there some kernel driver that works like sysfs so that these nodes are not traditional files?
>> 
>> What I am trying to understand is two things:
>> 
>> - Interaction with the power regulator
>> - Interaction with the host cpu
>> 
>> So my hope is someone can connect the dots of the path from the dbus to systemd through the targets to a service executable doing the work so I can try to replace them with:
>> 
>> - Something that turns the regulators on/off, with pmbus in this case.
>> - Something that can behave like a host to keep the system happy like a real system.
>> 
>> Mike
>> 
>> My repos
>> ——————
>> 
>> https://github.com/Proclivis/meta-pmbus-raspberrypi.git
>> https://github.com/Proclivis/meta-pmbus-phosphor.git
>> https://github.com/Proclivis/conf-openbmc-adi.git
>> 
>> The monitor messages for StartUnit
>> ———
>> 
>> method call time=1598039669.247458 sender=:1.48 -> destination=org.freedesktop.systemd1 serial=33 path=/org/freedesktop/systemd1; interface=org.freedesktop.systemd1.Manager; member=StartUnit
>>   string "obmc-host-start@0.target"
>>   string "replace"
>> method call time=1598039669.276170 sender=:1.3 -> destination=org.freedesktop.DBus serial=775 path=/org/freedesktop/DBus; interface=org.freedesktop.DBus; member=GetConnectionUnixUser
>>   string ":1.48"
>> method return time=1598039669.276234 sender=org.freedesktop.DBus -> destination=:1.3 serial=4294967295 reply_serial=775
>>   uint32 0
>> method call time=1598039669.280376 sender=:1.3 -> destination=org.freedesktop.DBus serial=776 path=/org/freedesktop/DBus; interface=org.freedesktop.DBus; member=AddMatch
>>   string "type='signal',sender='org.freedesktop.DBus',path='/org/freedesktop/DBus',interface='org.freedesktop.DBus',member='NameOwnerChanged',arg0=':1.48'"
>> method return time=1598039669.280661 sender=org.freedesktop.DBus -> destination=:1.3 serial=4294967295 reply_serial=776
>> method call time=1598039669.280701 sender=:1.3 -> destination=org.freedesktop.DBus serial=777 path=/org/freedesktop/DBus; interface=org.freedesktop.DBus; member=GetNameOwner
>>   string ":1.48"
>> method return time=1598039669.280738 sender=org.freedesktop.DBus -> destination=:1.3 serial=4294967295 reply_serial=777
>>   string ":1.48"
>> signal time=1598039669.280774 sender=:1.3 -> destination=(null destination) serial=778 path=/org/freedesktop/systemd1; interface=org.freedesktop.systemd1.Manager; member=UnitNew
>>   string "obmc-host-start@0.target"
>>   object path "/org/freedesktop/systemd1/unit/obmc_2dhost_2dstart_400_2etarget"
>> signal time=1598039669.280823 sender=:1.3 -> destination=(null destination) serial=779 path=/org/freedesktop/systemd1; interface=org.freedesktop.systemd1.Manager; member=JobNew
>>   uint32 1105
>>   object path "/org/freedesktop/systemd1/job/1105"
>>   string "obmc-host-start@0.target"
>> method return time=1598039669.280883 sender=:1.3 -> destination=:1.48 serial=780 reply_serial=33
>>   object path "/org/freedesktop/systemd1/job/1105"
>> signal time=1598039669.281305 sender=:1.48 -> destination=(null destination) serial=34 path=/xyz/openbmc_project/state/host0; interface=org.freedesktop.DBus.Properties; member=PropertiesChanged
>>   string "xyz.openbmc_project.State.Host"
>>   array [
>>      dict entry(
>>         string "RequestedHostTransition"
>>         variant             string "xyz.openbmc_project.State.Host.Transition.On"
>>      )
>>   ]
>>   array [
>>   ]

Re: Server Power On mystery

[Mike]

So for example, if a system had a PMbus HotSwap, a VR for the CPU, and an auxiliary PMBus sequencer for an FPGA, and an I2C mux, and the host and aux supplies required different state management, where they don’t sequence together, how would that be done? By learning how the current pieces play together I can imagine multiple new use cases and prototype them.

As for faking or neutering the host function, it’s just to remove side effects to prove out solutions.

Longer term are goals related to remote update of PMBus device EEPROM. Say, give file to webui, power supply settings are updated. More on that later from one of the PMBus technical working group. Stay tuned. But the raspi will be a basis for testing updates, assuming we succeed. 

These are little different goal than how do I do X for design Y.

What makes it hard is the documentation is not complete and folk knowledge required is high. I’m not complaining. It’s just reality.

Mike

Sent from my iPhone

> On Aug 24, 2020, at 1:11 PM, Mike <proclivis@gmail.com> wrote:
> 
> Ed,
> 
> My goals are atypical 
> 
> - Understand typical obmc use cases to see how various ADI devices would fit in: Hot Swap, Power Sequencers, PMBus regulators 
> - Try these use cases in raspi by neutering or faking the host
> - Create linux drivers to support obmc
> 
> Mike
> 
> Sent from my iPhone
> 
>> On Aug 24, 2020, at 12:41 PM, Ed Tanous <ed@tanous.net> wrote:
>> 
>> I think the best thing would be to start off by stating exactly what
>> you're trying to accomplish, and we can go from there.  As is, you're
>> using a raspberry pi, which doesn't have a "host" in the normal BMC
>> sense, so I'm really confused as to what you're hoping to do with the
>> host power button.  Are you trying to reboot the raspberry pi?  Reboot
>> a host connected through some other means?
>> 
>> -Ed
>> 
>>>> On Fri, Aug 21, 2020 at 3:29 PM Mike Jones <proclivis@gmail.com> wrote:
>>> 
>>> Hi,
>>> 
>>> I am trying to understand how the Server power button in the webui works.
>>> 
>>> As before, using raspberry pi, and I’ll leave project links at the end for anyone that wants to use them. Things work up to monitoring voltages. Note the conf project has a phosphor branch for the full monty.
>>> 
>>> To reverse engineer, I setup: dbus-monitor —system > someFile.log
>>> 
>>> There is a message for systemd1.Manager; member=StartUnit and best I can tell, somehow this gets routed to systemd to start some service or run some exe. I see this mentioned in the dbus transactions:
>>> 
>>> "obmc-host-start@0.target”
>>> 
>>> And that is in /lib/systemd/system and depends on obmc-host-startmin@0.target, but that does not depend on any service. So that is a dead end. It also depends on a reboot attempts, but I think that is not responsible for power on/off.
>>> 
>>> Then there are chassis services, but I cannot find a link from obmc-host-start@0.target to objc-chassis-poweron@0.target.
>>> 
>>> In this doc: https://github.com/openbmc/docs/blob/master/architecture/openbmc-systemd.md
>>> 
>>> It shows:
>>> 
>>> 
>>> ls -1 /lib/systemd/system/obmc-chassis-poweron\@0.target.requires/
>>> op-power-start@0.service
>>> op-wait-power-on@0.service
>>> 
>>> 
>>> But when I “ls” that path, the above dependencies are not there. There is only a dependency on phosphor-fan-presence-tach@0.service
>>> 
>>> There is some state service that lead to things with xzy paths, and I eventually found /run/systemd/units. These have file names starting with “invocation” in the names and link to GUID like nodes that don’t “cat” like a normal file. So I am not sure how those work. Is there some kernel driver that works like sysfs so that these nodes are not traditional files?
>>> 
>>> What I am trying to understand is two things:
>>> 
>>> - Interaction with the power regulator
>>> - Interaction with the host cpu
>>> 
>>> So my hope is someone can connect the dots of the path from the dbus to systemd through the targets to a service executable doing the work so I can try to replace them with:
>>> 
>>> - Something that turns the regulators on/off, with pmbus in this case.
>>> - Something that can behave like a host to keep the system happy like a real system.
>>> 
>>> Mike
>>> 
>>> My repos
>>> ——————
>>> 
>>> https://github.com/Proclivis/meta-pmbus-raspberrypi.git
>>> https://github.com/Proclivis/meta-pmbus-phosphor.git
>>> https://github.com/Proclivis/conf-openbmc-adi.git
>>> 
>>> The monitor messages for StartUnit
>>> ———
>>> 
>>> method call time=1598039669.247458 sender=:1.48 -> destination=org.freedesktop.systemd1 serial=33 path=/org/freedesktop/systemd1; interface=org.freedesktop.systemd1.Manager; member=StartUnit
>>>  string "obmc-host-start@0.target"
>>>  string "replace"
>>> method call time=1598039669.276170 sender=:1.3 -> destination=org.freedesktop.DBus serial=775 path=/org/freedesktop/DBus; interface=org.freedesktop.DBus; member=GetConnectionUnixUser
>>>  string ":1.48"
>>> method return time=1598039669.276234 sender=org.freedesktop.DBus -> destination=:1.3 serial=4294967295 reply_serial=775
>>>  uint32 0
>>> method call time=1598039669.280376 sender=:1.3 -> destination=org.freedesktop.DBus serial=776 path=/org/freedesktop/DBus; interface=org.freedesktop.DBus; member=AddMatch
>>>  string "type='signal',sender='org.freedesktop.DBus',path='/org/freedesktop/DBus',interface='org.freedesktop.DBus',member='NameOwnerChanged',arg0=':1.48'"
>>> method return time=1598039669.280661 sender=org.freedesktop.DBus -> destination=:1.3 serial=4294967295 reply_serial=776
>>> method call time=1598039669.280701 sender=:1.3 -> destination=org.freedesktop.DBus serial=777 path=/org/freedesktop/DBus; interface=org.freedesktop.DBus; member=GetNameOwner
>>>  string ":1.48"
>>> method return time=1598039669.280738 sender=org.freedesktop.DBus -> destination=:1.3 serial=4294967295 reply_serial=777
>>>  string ":1.48"
>>> signal time=1598039669.280774 sender=:1.3 -> destination=(null destination) serial=778 path=/org/freedesktop/systemd1; interface=org.freedesktop.systemd1.Manager; member=UnitNew
>>>  string "obmc-host-start@0.target"
>>>  object path "/org/freedesktop/systemd1/unit/obmc_2dhost_2dstart_400_2etarget"
>>> signal time=1598039669.280823 sender=:1.3 -> destination=(null destination) serial=779 path=/org/freedesktop/systemd1; interface=org.freedesktop.systemd1.Manager; member=JobNew
>>>  uint32 1105
>>>  object path "/org/freedesktop/systemd1/job/1105"
>>>  string "obmc-host-start@0.target"
>>> method return time=1598039669.280883 sender=:1.3 -> destination=:1.48 serial=780 reply_serial=33
>>>  object path "/org/freedesktop/systemd1/job/1105"
>>> signal time=1598039669.281305 sender=:1.48 -> destination=(null destination) serial=34 path=/xyz/openbmc_project/state/host0; interface=org.freedesktop.DBus.Properties; member=PropertiesChanged
>>>  string "xyz.openbmc_project.State.Host"
>>>  array [
>>>     dict entry(
>>>        string "RequestedHostTransition"
>>>        variant             string "xyz.openbmc_project.State.Host.Transition.On"
>>>     )
>>>  ]
>>>  array [
>>>  ]