I can't change my brighness via the default ubuntu tool or my FN keys, or even xbacklight. I'm running Ubuntu 12.04 on a laptop with a dual graphics (AMD HD6770M+Intel). I've the drivers set up properly and I can switch between them.
I've tried to adjust the brightness on both the integrated and discrete GPU. Nothing happens.
Any clue how do I go ahead fixing this? I've tried every solution here: Unable to change brightness in a Lenovo laptop