acpi brightness setting doesn't work

[Hendrik van Antwerpen]

Binary package hint: linux-source

1. Ubuntu version

Description: Ubuntu 8.10
Release: 8.10

2. Package version

Current: linux-image-2.6.27-11-generic (2.6.27-11.27)
Last known working: linux-image-2.6.27-9-generic (2.6.27-9.19)

3. Expected behaviour

On my Lenovo Thinkpad R61e, as root
$ cd /sys/class/backlight/acpi_video1
$ echo 0 > brightness # set brightness to lowest value
$ echo 0 > brightness # set brightness to highest value

The brightness of the LCD is expected to change with these commands.

4. Seen behaviour

Nothing happens when the commands above are executed.

5. Notes

Onder the -9 kernel, there are two acpi_videoX devices (0,1). The second one is the one actually working. When I remove video.ko (rmmod video) both devices disappear. Under the -11 kernel, there's only one device and removing video.ko has no effect on it.

I will attach the necessary files later, because I'm booted under the working kernel now.

[Tim Starling (tstarling)]

Assuming this jargon-heavy report can be translated into "Thinkpad brightness is totally broken in the latest Intrepid kernel", then I can confirm. Brightness changes via hotkeys and gnome-power-manager don't work. I'm running 2.6.27-11.27 on Lenovo R61.