I managed to solve the problem in a much cleaner way. I tried to create a custom xorg.conf file with the following content but my system didn't boot.
Section "Device" Identifier "Intel Graphics" Driver "intel" Option "Backlight" "intel_backlight" # use your backlight that works here EndSection Finally, I tried the following procedure: http://askubuntu.com/a/281685/27968 I got errors when starting lightdm BUT it created a xorg.conf.failsafe file. I opened it and modified it by adding the option line under "Device" as follows: Section "Device" Identifier "Configured Video Device" Driver "intel" Option "Backlight" "intel_backlight" EndSection # Section "Monitor" Identifier "Configured Monitor" EndSection # Section "Screen" Identifier "Default Screen" Monitor "Configured Monitor" Device "Configured Video Device" EndSection And bingo! Everything is working as it should. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1069144 Title: [Toshiba Satellite R830-1H3] brightness control works until sleep To manage notifications about this bug go to: https://bugs.launchpad.net/linux/+bug/1069144/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs