Brightness not working

Hey guys, I have the base model rMBP and the brightness buttons on my keyboard aren't working, they just show the image like I have no brightness... the same happens when I try to adjust it in System Preferences; it shows the brightness at the bottom end of the scale, I try to drag it up and when I let go the little slider goes back to the bottom of the scale. I also cannot click 'Automatically adjust brightness' - the button is like greyed out.

This is happening on both battery power and when plugged in, and for the record it looks like my screen is on full brightness.

I am updated to 10.8.1

EDIT
I restarted and it's working now, odd. I'd delete this thread if I could, apologies!