As this is seen both with Nvidia driver and nouveau driver, I guess this is not related to these drivers, but an issue in Xorg, or some communication between BIOS and kernel/Xorg to wake up the screen again.
This issue is reproducible by running "xset dpms force off; sleep 5; xset dpms force on" in a terminal inside X. ** Bug watch added: freedesktop.org Bugzilla #85459 https://bugs.freedesktop.org/show_bug.cgi?id=85459 ** Also affects: xorg-server via https://bugs.freedesktop.org/show_bug.cgi?id=85459 Importance: Unknown Status: Unknown -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xorg in Ubuntu. https://bugs.launchpad.net/bugs/1268151 Title: [Dell M4800] DPMS support broken, fails to wake up the monitor after putting it to sleep To manage notifications about this bug go to: https://bugs.launchpad.net/dell/+bug/1268151/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp
