“random pattern tiled across the whole screen” sounds very much like this: https://bugs.freedesktop.org/show_bug.cgi?id=61321
** Bug watch added: freedesktop.org Bugzilla #61321 https://bugs.freedesktop.org/show_bug.cgi?id=61321 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1181902 Title: Nouveau driver glitch on Ubuntu 13.04 will cause system to freeze under certain conditions To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-nouveau/+bug/1181902/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs