Re: [PATCH 0/3] Fix backlight issues on some Windows 8 systems

Felipe Contreras
2013-07-17T15:51:08Z

On Sat, Jun 22, 2013 at 4:46 PM, Yves-Alexis Perez <corsac@debian.org> wrote:
> On dim., 2013-06-09 at 19:01 -0400, Matthew Garrett wrote:
>> The first two patches in this series are picked from other patchesets aimed at
>> solving similar problems. The last simply unregisters ACPI backlight control
>> on Windows 8 systems when using an Intel GPU. Similar code could be added to
>> other drivers, but I'm reluctant to do so without further investigation as
>> to the behaviour of the vendor drivers under Windows.
>
> Hi,
>
> I've read this thread coming from
> https://bugzilla.kernel.org/show_bug.cgi?id=51231 and tried the patches
> on a Lenovo ThinkPad X230 with intel graphics.
>
> The problem with thoses fixes is that they still introduce a regression
> in how the brightness is handled, at least for me.

For me too.

> Before Linux support for acpi_osi("Windows 2012") (and when booting with
> acpi_osi="!Windows 2012"), brightness keys were handled by the kernel
> just fine, whether in console, in the display manager or in my desktop
> environment (Xfce). xfce4-power-manager just needs to be told that the
> brightness keys are already handled and it doesn't need to do anything.

How do you tell xfce4-power-manager that?

For me everything works fine when acpi_osi="!Windows 2012", which is
why I wrote a patch for this particular laptop.

http://article.gmane.org/gmane.linux.acpi.devel/60969

> So can the previous behavior be actually restored?

It *should*. The #1 rule of the Linux kernel is to never ever break
user-space, isn't it?

> Please keep me on CC: on replies, I'm not subscribed to the various
> lists.

You don't need to ask that in mailing lists that don't have reply-to
munged (sane ones), and vger ones don't.

Cheers.

--
Felipe Contreras