How to refresh the list of outputs detected by xrandr?

[Łukasz Maśko]

Hello.
I have a Dell E7250 laptop. I'm using it with docking stations with external 
monitors connected. I have one dock at home and another one at work. The 
monitors connected to them differ, both in models and connectors (and 
therefore are recognized as different xrandr outputs).

At home it looks like this:
$ xrandr
Screen 0: minimum 8 x 8, current 1920 x 1080, maximum 32767 x 32767
eDP1 connected primary 1920x1080+0+0 (normal left inverted right x axis y 
axis) 276mm x 156mm
   1920x1080     60.02*+  48.03  
   1400x1050     59.98  
   1280x1024     60.02  
   1280x960      60.00  
   1024x768      60.00  
   800x600       60.32    56.25  
   640x480       59.94  
DP1 disconnected (normal left inverted right x axis y axis)
DP1-1 disconnected (normal left inverted right x axis y axis)
DP1-2 disconnected (normal left inverted right x axis y axis)
DP1-3 connected (normal left inverted right x axis y axis)
   1440x900      59.89 +
   1280x1024     75.02    60.02  
   1280x960      60.00  
   1152x864      75.00  
   1152x720      59.97  
   1024x768      75.08    60.00  
   832x624       74.55  
   800x600       75.00    60.32    56.25  
   848x480       60.00  
   640x480       75.00    60.00    59.94  
   720x400       70.08  
DP2 disconnected (normal left inverted right x axis y axis)
HDMI1 disconnected (normal left inverted right x axis y axis)
HDMI2 disconnected (normal left inverted right x axis y axis)
VIRTUAL1 disconnected (normal left inverted right x axis y axis)

while at work like this:
$ xrandr
Screen 0: minimum 8 x 8, current 1920 x 1080, maximum 32767 x 32767
eDP1 connected primary 1920x1080+0+0 (normal left inverted right x axis y 
axis) 276mm x 156mm
   1920x1080     60.02*+  48.03  
   1400x1050     59.98  
   1280x1024     60.02  
   1280x960      60.00  
   1024x768      60.00  
   800x600       60.32    56.25  
   640x480       59.94  
DP1 disconnected (normal left inverted right x axis y axis)
DP1-1 connected (normal left inverted right x axis y axis)
   1920x1080     60.00 +  50.00    59.94  
   1600x1200     60.00  
   1680x1050     59.88  
   1280x1024     60.02  
   1440x900      59.90  
   1280x960      60.00  
   1280x800      59.91  
   1280x720      60.00    50.00    59.94  
   1024x768      60.00  
   800x600       60.32    56.25  
   720x576       50.00  
   720x480       60.00    59.94  
   640x480       60.00    59.94  
DP1-2 disconnected (normal left inverted right x axis y axis)
DP1-3 disconnected (normal left inverted right x axis y axis)
DP2 disconnected (normal left inverted right x axis y axis)
HDMI1 disconnected (normal left inverted right x axis y axis)
HDMI2 disconnected (normal left inverted right x axis y axis)
VIRTUAL1 disconnected (normal left inverted right x axis y axis)


The problem is, that if I suspend my laptop while it is connected to one of 
the docking stations, it remembers the layout of available monitors and when I 
dock it onto the other station and resume, it still shows me the old list of 
outputs and modes. I need to undock it while running and dock it again to make 
it notify the change in outputs.

Is there a software way to force xrandr to refresh its state and notify the 
change in connected devices?

I'm using PLD linux with kernel 4.2.6, xserver 1.17.4, xrandr 1.4.3. Thanks.
-- 
Łukasz Maśko                                                            _o)
Lukasz.Masko(at)ipipan.waw.pl                                           /\\
Registered Linux User #61028                                           _\_V
Ubuntu: staroafrykańskie słowo oznaczające "Nie umiem zainstalować Debiana"