Bug#448467: news about Thinkpad brightness keys situation

[Yves-Alexis Perez <corsac@debian.org>]

Hi,

I wanted to ask if there was any progress on the understanding of the
situation?

I have a Thinkpad T61 (8897 with intel G965), running Linux 2.6.25
(vanilla+thinkpad-acpi 0.19-20080321, but I can test with debian 2.6.25) and
xserver-xorg-video-intel 2.3.0-1 (experimental).

Brightness keys sure don't work out of the box (nor in console nor in Xorg).

acpid, powersaved and hald are running. I can stop them for testing if needed.

The driver by default uses the BACKLIGHT_CONTROL "kernel".

xbacklight works fine.

I have a /sys/class/backlight/acpi_video0 and 1. acpi_video0 does nothing, but
using acpi_video1 and echo'ing 0-15 to brightness works. But in that case,
xbacklight is lost.

xbacklight =100
# brightness is at full level
cat /sys/class/backlight/acpi_video1/actual_brightness
15 # acpi_video1 agree
echo 0 > /sys/class/backlight/acpi_video1/brightness
# brightness is at minimum level (but is not off, while it has worked at one
# time)
cat /sys/class/backlight/acpi_video1/actual_brightness
0 # acpi_video1 agree
xbacklight
100 # xbacklight disagree.

That's even without trying brightness keys.

Pressing brightness keys generates here acpi events video LCD0 87/86 (with
some delay, but I guess this one is a kernel problem). Nobody seems to catch
it, nor hal, nor powersaved, nor X driver.

I don't know what's the role of everybody involved, from the enduser pov,
something is wrong.

If you need more information, please ask, I'd be glad to provide stuff.

Cheers,
-- 
Yves-Alexis