* Power management for ppc 85xx
@ 2006-12-06 21:06 Chamorro, Marta
2006-12-06 21:50 ` Kumar Gala
0 siblings, 1 reply; 9+ messages in thread
From: Chamorro, Marta @ 2006-12-06 21:06 UTC (permalink / raw)
To: linuxppc-dev, linuxppc-embedded
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Hi there!
Hope someone out there can give me some pointers here. I've got a 2.6.18
kernel on a ppc 8555, which I configured to enable power management
(CONFIG_PM=y). After doing that, the file /sys/power/state appears on my
file system. If I cat the file I get "standby mem" (without the quotes),
but if I try to write to it (to change the state) I get an EPERM. I
assume it is because I have no code that implements any power save mode
changes, only the interface to change them. Am I wrong? How can I tell
for sure? (the file is writable, so it is not a problem with writing
permissions)
So the question is (if I am right) where do I get the code from? I am
hoping someone has implemented power save for that processor already,
but I just don't know where to start looking for that code. Can someone
help?
Thanks very much in advance.
Marta Chamorro.
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^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: Power management for ppc 85xx
2006-12-06 21:06 Power management for ppc 85xx Chamorro, Marta
@ 2006-12-06 21:50 ` Kumar Gala
2006-12-06 22:27 ` Chamorro, Marta
2006-12-07 19:57 ` Chamorro, Marta
0 siblings, 2 replies; 9+ messages in thread
From: Kumar Gala @ 2006-12-06 21:50 UTC (permalink / raw)
To: Chamorro, Marta; +Cc: linuxppc-dev, linuxppc-embedded
On Dec 6, 2006, at 3:06 PM, Chamorro, Marta wrote:
> Hi there!
>
>
>
> Hope someone out there can give me some pointers here. I=92ve got a =20=
> 2.6.18 kernel on a ppc 8555, which I configured to enable power =20
> management (CONFIG_PM=3Dy). After doing that, the file /sys/power/=20
> state appears on my file system. If I cat the file I get =93standby =20=
> mem=94 (without the quotes), but if I try to write to it (to change =20=
> the state) I get an EPERM. I assume it is because I have no code =20
> that implements any power save mode changes, only the interface to =20
> change them. Am I wrong? How can I tell for sure? (the file is =20
> writable, so it is not a problem with writing permissions)
I can pretty much say that there isn't any code that does pwr mgmt =20
for 85xx. I'm not sure what exactly your issue is, but there =20
definitely isn't any code.
> So the question is (if I am right) where do I get the code from? I =20
> am hoping someone has implemented power save for that processor =20
> already, but I just don=92t know where to start looking for that =20
> code. Can someone help?
Getting the core to nap is easy enough, doing proper power savings =20
for the full SoC maybe more challenging.
What exact behavior are you looking for? Something like suspend/=20
resume or just idle power savings?
- k=
^ permalink raw reply [flat|nested] 9+ messages in thread
* RE: Power management for ppc 85xx
2006-12-06 21:50 ` Kumar Gala
@ 2006-12-06 22:27 ` Chamorro, Marta
2006-12-06 22:53 ` Kumar Gala
2006-12-07 19:57 ` Chamorro, Marta
1 sibling, 1 reply; 9+ messages in thread
From: Chamorro, Marta @ 2006-12-06 22:27 UTC (permalink / raw)
To: Kumar Gala; +Cc: linuxppc-dev, linuxppc-embedded
Hi Kumar, thanks for the reply.
I am not sure I fully understand your question, but here's an attempt of
an answer :)
What I want to do is:
First stage - Get the processor on doze mode (core halted, but responds
to interrupts)
Second stage - Once I understand how to do that, using all the right
interfaces and so on, get other devices (mainly image processing ASICS)
to stop clocks.
Does that answer your question? Can you help? Do you know where to find
the code that deals with power management for the ppc 8555?=20
Regards,
Marta Chamorro
-----Original Message-----
From: Kumar Gala [mailto:galak@kernel•crashing.org]=20
Sent: 06 December 2006 21:51
To: Chamorro, Marta
Cc: linuxppc-dev@ozlabs•org; linuxppc-embedded@ozlabs•org
Subject: Re: Power management for ppc 85xx
On Dec 6, 2006, at 3:06 PM, Chamorro, Marta wrote:
> Hi there!
>
>
>
> Hope someone out there can give me some pointers here. I've got a =20
> 2.6.18 kernel on a ppc 8555, which I configured to enable power =20
> management (CONFIG_PM=3Dy). After doing that, the file /sys/power/=20
> state appears on my file system. If I cat the file I get "standby =20
> mem" (without the quotes), but if I try to write to it (to change =20
> the state) I get an EPERM. I assume it is because I have no code =20
> that implements any power save mode changes, only the interface to =20
> change them. Am I wrong? How can I tell for sure? (the file is =20
> writable, so it is not a problem with writing permissions)
I can pretty much say that there isn't any code that does pwr mgmt =20
for 85xx. I'm not sure what exactly your issue is, but there =20
definitely isn't any code.
> So the question is (if I am right) where do I get the code from? I =20
> am hoping someone has implemented power save for that processor =20
> already, but I just don't know where to start looking for that =20
> code. Can someone help?
Getting the core to nap is easy enough, doing proper power savings =20
for the full SoC maybe more challenging.
What exact behavior are you looking for? Something like suspend/=20
resume or just idle power savings?
- k
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: Power management for ppc 85xx
2006-12-06 22:27 ` Chamorro, Marta
@ 2006-12-06 22:53 ` Kumar Gala
2006-12-07 15:53 ` Chamorro, Marta
0 siblings, 1 reply; 9+ messages in thread
From: Kumar Gala @ 2006-12-06 22:53 UTC (permalink / raw)
To: Chamorro, Marta; +Cc: linuxppc-dev, linuxppc-embedded
On Dec 6, 2006, at 4:27 PM, Chamorro, Marta wrote:
> Hi Kumar, thanks for the reply.
>
> I am not sure I fully understand your question, but here's an
> attempt of
> an answer :)
>
> What I want to do is:
>
> First stage - Get the processor on doze mode (core halted, but
> responds
> to interrupts)
> Second stage - Once I understand how to do that, using all the right
> interfaces and so on, get other devices (mainly image processing
> ASICS)
> to stop clocks.
>
> Does that answer your question? Can you help? Do you know where to
> find
> the code that deals with power management for the ppc 8555?
It does, what periphs are you using on the 8555 itself?
- k
^ permalink raw reply [flat|nested] 9+ messages in thread
* RE: Power management for ppc 85xx
2006-12-06 22:53 ` Kumar Gala
@ 2006-12-07 15:53 ` Chamorro, Marta
2006-12-07 15:56 ` Kumar Gala
0 siblings, 1 reply; 9+ messages in thread
From: Chamorro, Marta @ 2006-12-07 15:53 UTC (permalink / raw)
To: Kumar Gala; +Cc: linuxppc-dev, linuxppc-embedded
Hi again,
Glad I managed to make sense. I checked the hardware spec on the board
and it looks like we're using everything, apart from the SEC and maybe
the stand-alone I2C (I think we're just using the one within the CMP).
By the way, I made a mistake and the actual processor on the board is
the cut-down 8541, not the 8555. My apologies for that.
This morning I added some printks and confirmed that there is no code
behind pm_ops, so my question remains: is there some code out there that
I can use? (hope so, otherwise I'm doomed...)
Regards and thanks,
Marta Chamorro
-----Original Message-----
From: Kumar Gala [mailto:galak@kernel•crashing.org]=20
Sent: 06 December 2006 22:53
To: Chamorro, Marta
Cc: linuxppc-dev@ozlabs•org; linuxppc-embedded@ozlabs•org
Subject: Re: Power management for ppc 85xx
On Dec 6, 2006, at 4:27 PM, Chamorro, Marta wrote:
> Hi Kumar, thanks for the reply.
>
> I am not sure I fully understand your question, but here's an =20
> attempt of
> an answer :)
>
> What I want to do is:
>
> First stage - Get the processor on doze mode (core halted, but =20
> responds
> to interrupts)
> Second stage - Once I understand how to do that, using all the right
> interfaces and so on, get other devices (mainly image processing =20
> ASICS)
> to stop clocks.
>
> Does that answer your question? Can you help? Do you know where to =20
> find
> the code that deals with power management for the ppc 8555?
It does, what periphs are you using on the 8555 itself?
- k
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: Power management for ppc 85xx
2006-12-07 15:53 ` Chamorro, Marta
@ 2006-12-07 15:56 ` Kumar Gala
2006-12-09 5:31 ` Clemens Koller
0 siblings, 1 reply; 9+ messages in thread
From: Kumar Gala @ 2006-12-07 15:56 UTC (permalink / raw)
To: Marta Chamorro; +Cc: linuxppc-dev, linuxppc-embedded
On Dec 7, 2006, at 9:53 AM, Chamorro, Marta wrote:
> Hi again,
>
> Glad I managed to make sense. I checked the hardware spec on the board
> and it looks like we're using everything, apart from the SEC and maybe
> the stand-alone I2C (I think we're just using the one within the CMP).
> By the way, I made a mistake and the actual processor on the board is
> the cut-down 8541, not the 8555. My apologies for that.
>
> This morning I added some printks and confirmed that there is no code
> behind pm_ops, so my question remains: is there some code out there
> that
> I can use? (hope so, otherwise I'm doomed...)
I'm sorry to say you're doomed. I don't believe anyone's spent any
time trying to do pwr mgmt on 85xx.
- k
> -----Original Message-----
> From: Kumar Gala [mailto:galak@kernel•crashing.org]
> Sent: 06 December 2006 22:53
> To: Chamorro, Marta
> Cc: linuxppc-dev@ozlabs•org; linuxppc-embedded@ozlabs•org
> Subject: Re: Power management for ppc 85xx
>
>
> On Dec 6, 2006, at 4:27 PM, Chamorro, Marta wrote:
>
>> Hi Kumar, thanks for the reply.
>>
>> I am not sure I fully understand your question, but here's an
>> attempt of
>> an answer :)
>>
>> What I want to do is:
>>
>> First stage - Get the processor on doze mode (core halted, but
>> responds
>> to interrupts)
>> Second stage - Once I understand how to do that, using all the right
>> interfaces and so on, get other devices (mainly image processing
>> ASICS)
>> to stop clocks.
>>
>> Does that answer your question? Can you help? Do you know where to
>> find
>> the code that deals with power management for the ppc 8555?
>
> It does, what periphs are you using on the 8555 itself?
>
> - k
>
>
>
^ permalink raw reply [flat|nested] 9+ messages in thread
* RE: Power management for ppc 85xx
2006-12-06 21:50 ` Kumar Gala
2006-12-06 22:27 ` Chamorro, Marta
@ 2006-12-07 19:57 ` Chamorro, Marta
1 sibling, 0 replies; 9+ messages in thread
From: Chamorro, Marta @ 2006-12-07 19:57 UTC (permalink / raw)
To: Kumar Gala; +Cc: linuxppc-dev, linuxppc-embedded
Hi again, Kumar,
You said on your first reply that it was easy to get the core to nap, so
that sounds like a suitable first step for me.
Any pointers? Is there, for instance, any ppc implementation of power
management I could look at to see how's done?
Thanks,
Marta
-----Original Message-----
From: Kumar Gala [mailto:galak@kernel•crashing.org]=20
Sent: 06 December 2006 21:51
To: Chamorro, Marta
Cc: linuxppc-dev@ozlabs•org; linuxppc-embedded@ozlabs•org
Subject: Re: Power management for ppc 85xx
On Dec 6, 2006, at 3:06 PM, Chamorro, Marta wrote:
> Hi there!
>
>
>
> Hope someone out there can give me some pointers here. I've got a =20
> 2.6.18 kernel on a ppc 8555, which I configured to enable power =20
> management (CONFIG_PM=3Dy). After doing that, the file /sys/power/=20
> state appears on my file system. If I cat the file I get "standby =20
> mem" (without the quotes), but if I try to write to it (to change =20
> the state) I get an EPERM. I assume it is because I have no code =20
> that implements any power save mode changes, only the interface to =20
> change them. Am I wrong? How can I tell for sure? (the file is =20
> writable, so it is not a problem with writing permissions)
I can pretty much say that there isn't any code that does pwr mgmt =20
for 85xx. I'm not sure what exactly your issue is, but there =20
definitely isn't any code.
> So the question is (if I am right) where do I get the code from? I =20
> am hoping someone has implemented power save for that processor =20
> already, but I just don't know where to start looking for that =20
> code. Can someone help?
Getting the core to nap is easy enough, doing proper power savings =20
for the full SoC maybe more challenging.
What exact behavior are you looking for? Something like suspend/=20
resume or just idle power savings?
- k
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: Power management for ppc 85xx
2006-12-07 15:56 ` Kumar Gala
@ 2006-12-09 5:31 ` Clemens Koller
2006-12-12 15:17 ` Chamorro, Marta
0 siblings, 1 reply; 9+ messages in thread
From: Clemens Koller @ 2006-12-09 5:31 UTC (permalink / raw)
To: Kumar Gala; +Cc: Marta Chamorro, linuxppc-embedded, linuxppc-dev
Hello, Kumar, Hi, Marta!
>> Glad I managed to make sense. I checked the hardware spec on the board
>> and it looks like we're using everything, apart from the SEC and maybe
>> the stand-alone I2C (I think we're just using the one within the CMP).
>> By the way, I made a mistake and the actual processor on the board is
>> the cut-down 8541, not the 8555. My apologies for that.
>>
>> This morning I added some printks and confirmed that there is no code
>> behind pm_ops, so my question remains: is there some code out there
>> that
>> I can use? (hope so, otherwise I'm doomed...)
>
> I'm sorry to say you're doomed. I don't believe anyone's spent any
> time trying to do pwr mgmt on 85xx.
I am working with the MPC8540 in a mobile product and some
power saving would be fine to use. But I haven't seen any
power management code for that thingy in the kernels at all.
So, there is some work left there. Maybe I will have
a closer look in the future.
According to some tests of a board manufacturer, the cpu
doesn't power down very much, when you stop some peripherals
or send the core to nap. But I wasn't able to confirm that yet.
Best greets,
Clemens Koller
_______________________________
R&D Imaging Devices
Anagramm GmbH
Rupert-Mayer-Str. 45/1
81379 Muenchen
Germany
http://www.anagramm-technology.com
Phone: +49-89-741518-50
Fax: +49-89-741518-19
^ permalink raw reply [flat|nested] 9+ messages in thread
* RE: Power management for ppc 85xx
2006-12-09 5:31 ` Clemens Koller
@ 2006-12-12 15:17 ` Chamorro, Marta
0 siblings, 0 replies; 9+ messages in thread
From: Chamorro, Marta @ 2006-12-12 15:17 UTC (permalink / raw)
To: Clemens Koller; +Cc: linuxppc-embedded
Hi Clemens,
>=20
> Hello, Kumar, Hi, Marta!
>=20
> >> Glad I managed to make sense. I checked the hardware spec on the
board
> >> and it looks like we're using everything, apart from the SEC and
maybe
> >> the stand-alone I2C (I think we're just using the one within the
CMP).
> >> By the way, I made a mistake and the actual processor on the board
is
> >> the cut-down 8541, not the 8555. My apologies for that.
> >>
> >> This morning I added some printks and confirmed that there is no
code
> >> behind pm_ops, so my question remains: is there some code out there
> >> that
> >> I can use? (hope so, otherwise I'm doomed...)
> >
> > I'm sorry to say you're doomed. I don't believe anyone's spent any
> > time trying to do pwr mgmt on 85xx.
>=20
> I am working with the MPC8540 in a mobile product and some
> power saving would be fine to use. But I haven't seen any
> power management code for that thingy in the kernels at all.
> So, there is some work left there. Maybe I will have
> a closer look in the future.
>=20
> According to some tests of a board manufacturer, the cpu
> doesn't power down very much, when you stop some peripherals
> or send the core to nap. But I wasn't able to confirm that yet.
We're estimating 2.5 watts saving on doze mode, in case that helps.
That's for a 8545 @ 800MHz
>=20
> Best greets,
>=20
> Clemens Koller
> _______________________________
Bfn,
Marta Chamorro
^ permalink raw reply [flat|nested] 9+ messages in thread
end of thread, other threads:[~2006-12-12 15:18 UTC | newest]
Thread overview: 9+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2006-12-06 21:06 Power management for ppc 85xx Chamorro, Marta
2006-12-06 21:50 ` Kumar Gala
2006-12-06 22:27 ` Chamorro, Marta
2006-12-06 22:53 ` Kumar Gala
2006-12-07 15:53 ` Chamorro, Marta
2006-12-07 15:56 ` Kumar Gala
2006-12-09 5:31 ` Clemens Koller
2006-12-12 15:17 ` Chamorro, Marta
2006-12-07 19:57 ` Chamorro, Marta
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