Comment 27 for bug 114677

Tom could you post your bios version? i went straight from 302 to 305, so i don't know which, if any, between the two fixed it.

another worthwhile test just to rule out acpi and other helpers completely is to
1) log out of gnome
2) switch to a virtual terminal (ctrl+alt+f1)
3) stop gnome: /etc/init.d/gdm stop
4) stop acpi: /etc/init.d/acpid stop /etc/init.d/acpi-support stop
5) make sure there are no instances of xbindkeys running: ps auxww | grep xbindkeys
then confirm that your brightness keys still work.