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

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Date:	Sat, 13 Mar 2010 10:16:19 +0100
From:	Corentin Chary <corentin.chary@...il.com>
To:	Fabio Comolli <fabio.comolli@...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

On Fri, Mar 12, 2010 at 9:07 PM, Fabio Comolli <fabio.comolli@...il.com> wrote:
> 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

Yep, I know, but un-revert the patch, and add a printk :p
Could you also send the result of:
/* clean boot */
cat cpufv
echo 0 > cpufv
cat cpufv
echo 1 > cpufv
cat cpufv

Thanks,

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