Comment 9 for bug 1178727

Christopher M. Penalver, thanks for your clear instructions.
I tested with linux-image-3.12.0-031200rc6-generic, and this problem persists.
I also found that when booting the machine, I can adjust the brightness when GRUB2 is loaded, and then when I boot into Ubuntu, I'm stuck at whatever brightness level I had in GRUB2.

Good hunting, and thanks!
I'll be happy to offer any more information you might need.