https://bugs.freedesktop.org/show_bug.cgi?id=94933
--- Comment #4 from Nicola Mori nicolamori@aol.com --- The freeze is only related to X, I guess. If, after triggering it, I'm quick enough to switch to a tty then the system is still responsive, I can log in and input commands to the shell (this is how I got the dmesg after the freeze). If instead I wait a bit after the freeze then the keyboard and the mouse become unresponsive, and pressing Ctrl+Alt+F2 has no effect. The system gets stuck with a black screen, the mouse cursor can still be moved around but clicks have no effect. The same happens when switching back to X from the tty after the "quick switch to tty" mentioned above.