Comment 66 for bug 643118

The change in g-s-d that triggered the broken screen will be reverted (in post-release updates), so the screen will come up like it should. There is however a bug in the video drivers that allows a broken screen mode to be selected.

crjackson, once you have recovered we can try to fix this. Please try radeon.modeset=0 and also try the newest kernel from http://kernel.ubuntu.com/~kernel-ppa/mainline/ when you have a chance. Get the Xorg.0.log, dmesg, and xrandr output in both cases.