Fix X11 Freeze

Sometimes it happens that my UBUNTU Box freezes. Especially after extensive usage of the media. Here are two methods to handle this issue:

1- Going to a different virtual console.

Alt+Ctr+F1 (or F2, .... , F6)

After logging, you can restart the X server using:
$sudo service lightdm restart




P.S: This assumes that your display manager is lightdm (True for ubuntu 12.04). You can check your agent using /etc/X11/default-display-manager


2- If you cannot change to another virtual console, b/c the X server took control of the keyboard. You can try taking the control away from the X server using Sysrq.

Alt+SysRq+r

then try Ctr+Alt+F1.  You can also try Alt+SysRq+k, which kills all programs on the current console.