Comment 0 for bug 1722448

I used 14.04 for many years with this problem, but recently "upgraded" to 16.04.

Since then using multiple monitors causes X to randomly freeze.

After searching similar bugs I found that a "killall -9 compiz" from an SSH login un-freezes it.

However, if the system gets into this state once, it happens more frequently.

I found the problem occurred when using multiple workspaces on multiple monitors, so I stopped using multiple workspaces.

To my surprise, the problem continued to happen.

So, the problem may be related multiple monitors.