This fixed a black screen issue and a brightness adjustment issue after installation of ubuntu. Also on 11.04 I couldn't get Unity to work until I edited grub I didn't come up with the fix but it took me forever to find a solution so I figured I would post it. If I have did something wrong just get a mod to delete or move this. I don't use forums often.
sudo gedit /etc/default/grub
Edit two lines to read as follows:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"