Since I upgrade from ubuntu 12.10 to 13.04 I can't change the brightness of the display, it remain in the darkest possible mode. I have a Dell 3721 laptop. Any advice?
@Dell:~$ lspci -nn | grep VGA 00:02.0 VGA compatible controller : Intel Corporation 3rd Gen Core processor Graphics Controller [8086:0166] (rev 09)
If I use this, I can change the brigntess, but its so uncomfortable, why I cant use the hotkeys or ubuntu system controll anymore?
echo 3500 | sudo tee /sys/class/backlight/intel_backlight/brightness