This is caused by having the nvidia proprietary drivers installed. They replace libGL with a version that doesn't work for Intel (or radeon), and produces the strange inverted display you see.
If you haven't deliberately installed the nvidia drivers then this was probably caused by a bug in a previous version of the mplayer packaging, which would incorrectly cause the nvidia drivers to be installed. ** Changed in: xserver-xorg-video-intel (Ubuntu) Status: Confirmed => Invalid -- system GUI turn upside down when visual effects changed from none to normal https://bugs.launchpad.net/bugs/267269 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