Bug#448467: xserver-xorg-video-intel: Thinkpad brightness keys don't work
On Saturday, December 22, 2007 9:12 am Brice Goglin wrote:
> Henrique de Moraes Holschuh wrote:
> > On Sat, 15 Dec 2007, Marcus Better wrote:
> >> I just tried with a new one, but the brightness is still broken.
> >> It requires "native" or "combination" mode.
> > I'd like to see X.org talking to the kernel to find out and
> > coordinate which mode should be used...
> Could you please have a look at
> and see if you can find a solution with the thinkpad guys for correct
> backlight handling? Marcus tried with intel git about a week ago, it
> didn't go very well.
The backlight situation is rather unfortunate. As you've already
discovered, there are several different ways backlights are controlled
on various platforms, and some of them are incompatible.
The Intel X driver now tries to talk to the kernel drivers directly (via
the /sys/class/backlight interface) starting with the thinkpad_screen
driver, followed by acpi_video1 and acpi_video0. Depending on how your
kernel is configured, this may work perfectly or result in the drivers
fighting one another for backlight adjustments.
Since on Thinkpads, the kernel method is available (either via the
kernel thinkpad driver or ACPI) you should try to use that, but it may
be that the acpi_video1 method is your best choice. You can try that
interface by changing the order of the string array in i830_lvds.c
around line 67.
If you want to use one of the other methods (which may provide you with
more possible backlight levels) you should unload all kernel backlight
drivers prior to loading X (or disabling their backlight interfaces as
in the case of the thinkpad driver); that may give you a good user
Sorry if I missed anything in the initial bug report, I'm on vacation at
my mother-in-law's right now, with a free wireless connection kindly
provided by someone called 'jazzman' (at least according to his