Can't control backlight on Intels GM965 with neither xbacklight nor gnome-power-manager

Binary package hint: xbacklight

I can't control the brightness of my x61s after switching from gutsy to hardy.

I was able to lighten or dim my display in two ways, either with the function keys through some GNOME applet, or via xbacklight. Both ways didn't depend on each other, i.e. I could do 100% via the GNOME thing and 0% via xbacklight and the diplay would be dark.

The GNOME changes were visible through /sys/class/backlight/acpi_video0/brightness and the xbacklight changes via "xbacklight -get".

Both way don't work anymore. However, the xbacklight method still works, after I do a xrandr --output LVDS --set BACKLIGHT_CONTROL native as mentioned in bug 176888.

The GNOME method doesn't work at all. I can press the function keys and get this OSD which shows me the changes to brightness, the display however, doesn't change it's brightness at all. And the files in /sys/class/backlight/ don't change at all.

That's a pity because the tight integration of gnome-power-manager is useless, as it's not able to control my displays power consumption.

FWIW: The "Thinkvantage Key" and Power Key don't work any more as well. They used to make an event, but they don't anymore. Maybe some ACPI code got buggy.

Please let me know how to debug this issue or what information I can provide to fix this bug.