I've got a Vaio S11 laptop with Nvidia 310M graphics running Ubuntu 13.04 with nvidia graphics driver (nvidia-310). Backlight control started working since I created a .conf file in /usr/share/X11/xorg.conf.d with lines:
Section "Device" Identifier "Device0" Driver "nvidia" VendorName "NVIDIA Corporation" Option "RegistryDwords" "EnableBrightnessControl=1" EndSection
Keyboard backlight control (Fn+F5/Fn+F6) either works from the system startup time or does not at all (after reboot it can start working again). Slider in the system settings always works fine.
How do I fix keyboard control?