The brightness keys on my Dell N4010 with Ubuntu 12.04 is causing ubuntu to freeze on a black screen if i press the BrightUp and BrightDown key(s) 3-4 times. I think this is a bug which was noticed in 10.04 and was patched, but its giving problem in 12.04 again to me. I tried remapping and disabling the brightness keys but it did not work out. Please help.
Edit "/etc/default/grub" as root.
Now, look for the line that looks like:
Append "acpi_backlight=vendor acpi_osi=Linux" to the end of that line, before the end quotes, so that the line now looks something like this:
Save and close the file, and run the following command:
Now, reboot, and test out the brightness keys. They should be working correctly now.