The X server on Linux provides your graphical desktop.If it crashes, you’ll
lose all unsaved work in graphical
programs,but you can recover from the crash and
restart the X server without restarting
X server crashes can be caused by bugs with graphics drivers – the proprietary
AMD or NVIDIA graphics drivers, for example – hardware problems, or other software bugs.
After it’s enabled, you can press Ctrl+Alt+Backspace to immediately restart your X server. However, this shortcut is implemented by the X server and may not work if X hangs in some ways.
Switch Virtual ConsolesYou can use the Ctrl+Alt+F1 keyboard shortcut (and other F-key keyboard shortcuts) to switch to a different virtual console from your X server. (Ctrl+Alt+F7 usually takes you back to X – the exact F key depends on your Linux distribution.)
Once you have, you can log into the virtual console and run the appropriate command to restart your X server. The command you’ll need depends on the display manager you’re using. On Ubuntu, which uses the LightDM display manager, you’d use the following command:
sudo service lightdm restart
SSH Into ComputerIf you can’t kill the X server locally, you can kill it over the network. Assuming you have anSSH server set up and running on your Linux system, you can log in from another computer and run the appropriate command to restart the X server. Just sign in via SSH to access a remote console and use the appropriate command to restart your display manager – on Ubuntu, it’s the sudo service lightdm restart command above.
Use the Magic SysRq Key
We’ve covered using the magic SysRq key in the past – the SysRq is is generally the same as the Print Screen key. Assuming you want to kill the X server locally – not over the network – your system may not be responding to key presses, including the Ctrl+Alt+F1 keyboard shortcut. This can occur because the X server has taken control of the keyboard. To take control away from the X server, use the following key combination:
After you have, you can try pressing Ctrl+Alt+F1 to access a virtual console. You can also use the Alt+SysRq+k combination, which kills all programs on your current virtual console, including your X server.
If you want to restart your computer, you can also use the magic SysRq key to cleanly restart your system