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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <b637ec0b1003111328u5c1d7d7fw6c76c409740827c7@mail.gmail.com>
Date:	Thu, 11 Mar 2010 22:28:50 +0100
From:	Fabio Comolli <fabio.comolli@...il.com>
To:	ACPI mailing list <linux-acpi@...r.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Corentin Chary <corentin.chary@...il.com>
Cc:	Len Brown <lenb@...nel.org>
Subject: Re: Possible bug in eeepc-laptop.c - EeePC 900

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
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/