I'm using a Lenovo Thinkpad X120e with Ubuntu 12.04 LTS 64-bit and a Gnome 3.4 (gnome-shell) desktop environment. I have installed the latest proprietary AMD drivers (From their website) for the AMD Radeon HD 6250 graphics card.
My problem is that once the mouse appears on the screen at startup, the backlight controls (Fn+Delete/Home) stop working. While it's booting up, I can control the brightness just fine. At first it wouldn't work at all, but turning off Vari-Bright in Catalyst Control Center fixed it. Once logged in the OSD works fine, but brightness control does not work, so it's no a keyboard shortcut issue. I have tried adding
acpi_osi=, and combinations of the two options to the grub config and they do not do anything (of course I ran
grub-update). I have also tried adding
Option "RegistryDwords" "EnableBrightnessControl=1" to the
Device section of xorg.conf (I belive this is for Nvidia drivers, but doesn't hurt to try), and combined this with the grub configs, and this also does nothing.
I am running out of options here. It's not so bad, but quite annoying during the evening when I want to turn the brightness down.
Anybody know how to fix this?