I couldn't change brightness of my Sony EH18FA laptop with Ubuntu 13.04. My laptop has Nvidia Geforce 410M GPU.
I am using Ubuntu 13.04 along with Windows 7 Home Basic.
The brightness can't be changed using (Fn + F6 or F5) keys nor from system sittings, although the slider changed but the brightness of screen not changed.
I tried a lot of recommended solutions but no one of them worked. I am afraid that I need install some drivers or something like that.