Comment # 22 on bug 46711 from Marcus

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)