gistfile1.txt

~ xrandr -q
Screen 0: minimum 8 x 8, current 3520 x 1080, maximum 32767 x 32767
LVDS1 connected 1600x900+0+0 (normal left inverted right x axis y axis) 382mm x 214mm
   1600x900      60.06*+
   1024x768      60.00  
   800x600       60.32    56.25  
   640x480       59.94  
VGA1 connected (normal left inverted right x axis y axis)
   1280x1024     75.02    75.02    60.02  
   1152x864      75.00  
   1024x768      75.08    70.07    60.00  
   832x624       74.55  
   800x600       75.00    60.32  
   640x480       75.00    60.00    59.94  
   720x400       70.08  
HDMI1 connected 1920x1080+1600+0 (normal left inverted right x axis y axis) 475mm x 267mm
   1920x1080     60.00*+  50.00  
   1920x1080i    50.00    60.00  
   1680x1050     59.88  
   1600x900      59.98  
   1280x1024     60.02  
   1440x900      59.90  
   1280x960      60.00  
   1280x720      50.00    60.00  
   1024x768      60.00  
   1440x480i     59.94  
   800x600       60.32  
   720x576       50.00  
   720x480       59.94  
   640x480       60.00    59.94  
   720x400       70.08  
DP1 disconnected (normal left inverted right x axis y axis)
VIRTUAL1 disconnected (normal left inverted right x axis y axis)
-------------                                                                           
~ 

gistfile2.txt

~ xrandr --output VGA1 --mode 1280x1024 --left-of HDMI1
xrandr: Configure crtc 2 failed
-------------    
~ xrandr --output HDMI1 --mode 1920x12900 --right-of LVDS1

# The other screen is already connected.
# Any combination of two of {LVDS1, HDMI1, VGA1} works fine