Look at this video clip to see what happen after I work up my monitor from sleep https://www.youtube.com/watch?v=XxcQhPmF374&feature=youtu.be Reproducible: Didn't try Steps to Reproduce: 1. Put monitor to sleep 2. Wake PC up 3. Monitor rendering goes crazy, unviewable Actual Results: monitor were viewable Expected Results: system should wake to usable state I have a dual monitor setup, system was updated from 14.10 to 15.04
This is a problem with kwin and GPU drivers (I can reproduce it at home with my nvidia binary drivers). The fix is usually to toggle compositing in KWin (Alt + Shift + F12).
*** This bug has been marked as a duplicate of bug 344326 ***