Fix external Displays switching not on when plugging notebook in docking station

If your external displays not switching on or showing a weird behavior (for e.g. all displays getting the same configuration all the time) you can fix it by switching off all external displays and re-enabling only one in the first step. Afterwards you can apply your whole configuration via xrandr. This behavior could be a bug in the kernel and may be fixed in linux 4.8.

Example display configuration

Screen 0: minimum 8 x 8, current 5760 x 1200, maximum 32767 x 32767
eDP1 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 276mm x 155mm
   1920x1080     60.00*+  59.93  
   1680x1050     59.95    59.88  
   1600x1024     60.17  
   1400x1050     59.98  
   1600x900      60.00  
   1280x1024     60.02  
   1440x900      59.89  
   1280x960      60.00  
   1368x768      60.00  
   1360x768      59.80    59.96  
   1152x864      60.00  
   1280x720      60.00  
   1024x768      60.00  
   1024x576      60.00  
   960x540       60.00  
   800x600       60.32    56.25  
   864x486       60.00  
   640x480       59.94  
   720x405       60.00  
   640x360       60.00  
DP1 disconnected (normal left inverted right x axis y axis)
DP2 disconnected (normal left inverted right x axis y axis)
DP2-1 connected primary 1920x1200+3840+0 (normal left inverted right x axis y axis) 518mm x 324mm
   1920x1200     59.95*+
   1920x1080     60.00  
   1600x1200     60.00  
   1680x1050     59.95  
   1280x1024     60.02  
   1280x960      60.00  
   1024x768      60.00  
   800x600       60.32  
   640x480       60.00  
   720x400       70.08  
DP2-2 connected 1920x1200+1920+0 (normal left inverted right x axis y axis) 518mm x 324mm
   1920x1200     59.95*+
   1920x1080     60.00  
   1600x1200     60.00  
   1680x1050     59.88  
   1280x1024     60.02  
   1280x960      60.00  
   1024x768      60.00  
   800x600       60.32  
   640x480       60.00  
   720x400       70.08  
DP2-3 disconnected (normal left inverted right x axis y axis)

disable external displays connected via DP

xrandr --output DP2-1 --off --output DP2-2 --off

enable just one of the external displays
```
xrandr  --output DP2-2 --auto
```

now you can apply your display configuration. in my case it looks like this:

xrandr --output eDP1 --auto --output DP2-2 --auto --primary --pos 1920x0 --right-of eDP1 --output DP2-1 --auto --pos 3840x0 --right-of DP2-2

You can stick your commands together and for e.g. apply them with a udev rule when attaching external displays:

xrandr --output DP2-1 --off --output DP2-2 --off && xrandr  --output DP2-2 --auto && xrandr --output eDP1 --auto --output DP2-2 --auto --primary --pos 1920x0 --right-of eDP1 --output DP2-1 --auto --pos 3840x0 --right-of DP2-2

Claus-Theodor Riegg

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Last edit

2016-11-29

Claus-Theodor Riegg

License

Source code in this card is licensed under the MIT License.

Posted by Claus-Theodor Riegg to makandra dev (2016-11-29 10:10)