Comment 2 for bug 360984

I have exactly the same problems.
When I try to use brightness keys seems that ubuntu "understands" what I'm doing, because on the top-right of the screen appears the brightness bar (like the volume one, when I change the volume) but it is "blocked".

I have to add that it's possible to increase/decrease brightness using "brightness applet" but only if the nvidia drivers are disabled.

I hope it can help.

thanks,
Stefano