to fix this issue start in safe mode and wait for command prompt may take awhile then do "lspci" look for ati vga.Then write down pci bus number mine was 1:00:0 restart again in safe mode and wait for the command promt.Then do sudo dpkg-reconfigure xserver-xorg you will then see options to set up graphics choose ati then press tab then enter set up everything then when you get busid put in the number you wrote down.Then finish off set up and restart hope this helps. im using ati radeon 9250
-- [regression][rv280] black screen and console freeze when X starts - drm lockup https://launchpad.net/bugs/67487 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs