Ubuntu 11.10 and Brightness Problem

On some labtops (for example some of sony F series labtops) brightness levels may not work after installation. Keyboard shortcut works and indicator shows brightness is increased or decreased but brightness of the monitor does not change. In my case solution was adding highlighted line below to /etc/X11/xorg.conf file (depending on your system you may add it in /etc/X11/xorg.conf.d/20-nvidia.conf file) and restarting X using sudo service lightdm restart.

Section "Device"
  Identifier     "Device0"
  Driver         "nvidia"
  VendorName     "NVIDIA Corporation"
  Option  "NoLogo"        "True"
 Option "RegistryDwords" "EnableBrightnessControl=1"
Ubuntu 11.10 and Brightness Problem, 5.0 out of 10 based on 2 ratings