2011 8,3 MacBook Pro running 64bit 11.10.

The screen brightness keys seem to actually do things, but nothing actually changes with regard to actual laptop screen brightness. (See this video. Ubuntu can sense when the buttons are pressed, but nothing actually happens with screen brightness. I know you wouldn't be able to see it if it did work, but it doesn't.)

Is this a known issue? How can I adjust the screen brightness on my MacBook Pro?

I know I can do something like this in the AMD/ATI FGLRX configuration software, but it actually just adjusts the output picture, not the physical laptop's screen brightness. What can I do?