Comment 3 for bug 368506

This happens on my Asus x5dij, too.

However, i think the issue with the brightness-keys has nothing to do with gnome-power-manager, since I incidentally discovered a workaround (see #399675).
Also, setting the brightness by writing to /sys/devices/virtual/backlight/acpi_video0/brightness works perfectly.

I assume the flickering occurs because before every brightness change the value is first set to the darkest and then to the desired one.

I'll soon test it with an karmic alpha live cd.