Bug#448467: xserver-xorg-video-intel: Thinkpad brightness keys don't work

[Marcus Better <marcus@better.se>]

Brice Goglin wrote:
> Also, there is now 4 strategies to manipulate the backlight: kernel,
> native, legacy or combination. The driver selects one by default
> depending on the hardware. Which one do you get at startup?

~$ xrandr --prop
Screen 0: minimum 320 x 200, current 1024 x 768, maximum 1024 x 1024
VGA disconnected (normal left inverted right x axis y axis)
LVDS connected 1024x768+0+0 (normal left inverted right x axis y axis) 
304mm x 228mm
        EDID_DATA:
                00ffffffffffff0030ae404000000000
                010f0103801e1778ea87f594574f8c27
                27505421080001010101010101010101
                01010101010164190040410026301888
                360030e4100000182815004041002630
                1888360030e4100000180000000f0061
                43326143280f010006af5125000000fe
                0041554f423135305847303256350051
        BACKLIGHT_CONTROL: kernel
                supported: native       legacy       combination  kernel
        BACKLIGHT: 60 (0x0000003c) range:  (0,100)
   1024x768       60.0*+   50.0
   800x600        60.3
   640x480        60.0     59.9

> Does it help if you change to another one,
> with for instance xrandr --output LVDS --set BACKLIGHT_CONTROL legacy ?

Yes, it works when set to "native" or "combination"!

With "kernel", the on-screen display does not show up at every press of 
the brightness key, and it quickly gets stuck at 42%.

With "legacy" the on-screen display goes up and down but the brightness 
is not changed.

This is so far with the current packaged video driver.

Marcus