Thanks, this sounds sort of like a modesetting issue and probably should go upstream. That would explain why the behavior varies on different resolutions. Does it work properly if you boot with the radeon.modeset=0 grub option?
** Changed in: xserver-xorg-video-ati (Ubuntu) Importance: Undecided => Medium ** Changed in: xserver-xorg-video-ati (Ubuntu) Status: Confirmed => Triaged -- [lucid] [LENOVO T60] external screen display shows "shivering", horizontal refresh offset https://bugs.launchpad.net/bugs/541501 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs