https://bugs.freedesktop.org/show_bug.cgi?id=46711
--- Comment #22 from Marcus marcus.hewat@gmail.com --- I have the problem each time I turn off my monitor and then later turn it back on. The desktop does not come back.
(In reply to Wolfgang Rupprecht from comment #4)
xset dpms force off sleep 1 xset dpms force on
This also gets the display back for me.
The monitor is a Samsung U24E850 (24 inch, 3840x2160)
The OS is Ubuntu 15.04 with 4.1.1 kernel installed and olibaf xork packages.
here is the relevant package information:
linux-image-4.1.1-040101-generic 4.1.1-040101.201506291635 xserver-xorg-video-radeon 1:7.5.99+git1507100730.b6d871~gd~v xserver-xorg-core 2:1.17.1-0ubuntu3
# xrandr Screen 0: minimum 320 x 200, current 3840 x 2160, maximum 16384 x 16384 DisplayPort-0 connected primary 3840x2160+0+0 (normal left inverted right x axis y axis) 521mm x 293mm 3840x2160 60.0*+ 2560x1440 60.0 1920x1080 60.0 59.9 1680x1050 60.0 1600x900 59.9 1280x1024 60.0 1440x900 59.9 1280x800 59.8 1280x720 59.9 1024x768 60.0 800x600 60.3 56.2 640x480 60.0 59.9 HDMI-0 disconnected (normal left inverted right x axis y axis) DVI-0 disconnected (normal left inverted right x axis y axis) DVI-1 disconnected (normal left inverted right x axis y axis)