Hi Austin,
We can make or modify some driver to "setting" CPU into some state. And the
whole process need no intervention from user mode.
We want to know whether moblin has some low level interface or driver which
can make CPU enter some power state. And we can invoke them to set CPU state
which is most like deciding by OS as you mentioned.
Message: 9
Date: Wed, 16 Sep 2009 14:41:59 +0800
From: "Zhang, Austin" <austin.zh...@intel.com>
To: ??? <lyj_upt...@126.com>, Arjan van de Ven
<ar...@linux.intel.com>
Cc: dev <dev@moblin.org>
Subject: Re: [Moblin Dev] low power state of atom
Message-ID:
<38d9f46dff92c54980d2f2c1e8ee313001ab921...@pdsmsx503.ccr.corp.intel.com>
Content-Type: text/plain; charset="gb2312"
> how can we get this tool.so we can exactly know which C and P states the
system using.
> then,
> how can we set the CPU into Deeper sleep?like pxa270?we can change
cpu mode by writting cp15 register
>
> we check the datasheet of both z5xx and SCH(us15wx) ,but find no
description of how can we generate the signals which can force CPU enter
Deeper sleep.
Why not google :)
http://www.lesswatts.org/projects/powertop/
Again, like arjan said, when you are trying to 'setting' it, that means your
cpu is working, so at this kind of situation, you CAN NOT enter into deep c
because cpu is working to your task.
Please let OS/CPU decide when and which level it should go to rather than
'setting' it.
> my purpose is to check the cpu Actual power loss when cpu work in Deeper
sleep(C4)?or Deep power down(C6)?.
Maybe you should use some physical device like power meter rather than by
'setting something and check it' for this purpose.
-----Original Message-----
From: dev-boun...@moblin.org [mailto:dev-boun...@moblin.org] On Behalf Of
???
Sent: Wednesday, September 16, 2009 2:20 PM
To: Arjan van de Ven
Cc: dev
Subject: Re: [Moblin Dev] low power state of atom
Hi?
thanks for your answer?
first?
?I suspect that your system WILL go into C4.
If you are not sure, you can run the powertop tool,?how can we get
this tool.so we can exactly know which C and P states the system using.
then,
how can we set the CPU into Deeper sleep?like pxa270?we can change
cpu mode by writting cp15 register
we check the datasheet of both z5xx and SCH(us15wx) ,but find no
description of how can we generate the signals which can force CPU enter
Deeper sleep.
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