As the title says, in 12.04, when I hold FN and press the up and down arrow keys to adjust my screen brightness, the screen starts to flicker, and the OS freezes. I have to hold the power button to force it to shut down, and start it back up. I can't seem to adjust the brightness.
I had this bug on my Samsung laptop. The trick that fixed everything for me was to add a boot parameter to grub during loading. You can test to see if it works first by rebooting the machine and pressing
If it works, you can make it permanent by editing