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

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Date:	Fri, 12 Mar 2010 09:49:55 +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 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,


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