linux-kernel - Re: Possible bug in eeepc-laptop.c

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Date:	Fri, 12 Mar 2010 21:07:38 +0100
From:	Fabio Comolli <fabio.comolli@...il.com>
To:	Corentin Chary <corentin.chary@...il.com>
Cc:	ACPI mailing list <linux-acpi@...r.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Len Brown <lenb@...nel.org>
Subject: Re: Possible bug in eeepc-laptop.c - EeePC 900

Hi

On Fri, Mar 12, 2010 at 9:49 AM, Corentin Chary
<corentin.chary@...il.com> wrote:
> On Thu, Mar 11, 2010 at 10:28 PM, Fabio Comolli <fabio.comolli@...il.com> wrote:
>> Hi.
>>
>> On Tue, Mar 9, 2010 at 11:58 PM, Fabio Comolli <fabio.comolli@...il.com> wrote:
>>> Hi.
>>> I have an EeePC 900 running 2.6.34-rc1.
>>>
>>> If I boot it on AC the cpu runs at full speed, 900MHz; if I boot it on
>>> battery it runs only at 630Mhz. Plugging / unplugging the AC does not
>>> change the cpu frequency. Only a reboot can change the situation.
>>>
>>> I already tried to echo 0 or 1 to the
>>> /sys/devices/platform/eeepc/cpufv file; no effects, even if the file
>>> changes its value.
>>>
>>> This is not a regression from 2.6.33: this behavior is also present in
>>> that version.
>>>
>>> Does this ring any bells? This is really annoying, especially when
>>> trying to watch a movie on battery. Also 3D apps show a 30%
>>> performance drop, as expected.
>>>
>>> Regards,
>>> Fabio
>>
>> Well, it turns out that this is indeed a regression, but I don't know
>> from which kernel version.
>> I reverted (not cleanly) this patch:
>>
>>        http://patchwork.kernel.org/patch/28591
>>
>> and now
>>
>>        echo 1 > /sys/devices/platform/eeepc/cpufv
>>
>> enables the powersave mode and
>>
>>        echo 0 > /sys/devices/platform/eeepc/cpufv
>>
>> enables the performance mode.
>>
>> Tested with the non-benchmark glxgears (275 frames/sec in powersave
>> mode and 405 in performance mode) and stellarium (14 frames and 20
>> frames).
>>
>> Regards,
>> Fabio
>>
>
> Thanks for the report,
> Could you try to add a quick printk to show the value stored in
> set_acpi(CM_ASL_CPUFV, value); ?
> And also, could you send the result of acpidump ?
> Thanks,

After the revert there is no set_acpi(CM_ASL_CPUFV, value) anymore.
Please find the acpidump in attachment.

Regards,
Fabio



>
>
> --
> Corentin Chary
> http://xf.iksaif.net
>

View attachment "acpidump.txt" of type "text/plain" (117526 bytes)