After upgrading to 13.04 from Xubuntu 12.10, my monitor no longer goes to sleep automatically, and if I manually put it in sleep mode via xset dpms force off, it clicks back on after 10-15 seconds, though the screensaver remains active the whole time. I did not have this problem in 12.10. In Power Manager, On AC, Monitor, I have it set to put the display to sleep after 10 minutes / off after 15. Any ideas?
Bookmarks