Brian has hit the nail on the head with this one. As I am pressed for time I will only briefly outline some steps that eventually (after a few minutes) seem to result in this bug:
Run the following two scripts in separate terminals as a regular user: while true; do totem /usr/share/example-content/Experience\ ubuntu.ogg; done while true; do sleep 10; killall totem; done; Run the following script in a root terminal (i.e. one you have sudo'd to root in): while true; do chvt 2; sleep 3; chvt 7; sleep 3; done Now a variety of things will happen: 1. You may get the infamous flashing grey block lockup 2. You may find you VT consoles go funny colours but you can still switch back to X and X appears to be fine. 3. You may find that totem suddenly refuses to play videos and looking in dmesg shows something similar to the following: no MTRR for d0400000,200000 found mtrr: no more MTRRs available -- laptop hangs when switching video mode https://bugs.launchpad.net/bugs/127101 You received this bug notification because you are a member of Ubuntu Bugs, which is the bug contact for Ubuntu. -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
