Ubuntu - X - Get Resolutions

xrandr

returns:

Screen 0: minimum 8 x 8, current 3440 x 1440, maximum 32767 x 32767
DVI-D-0 disconnected (normal left inverted right x axis y axis)
HDMI-0 disconnected (normal left inverted right x axis y axis)
DP-0 connected primary 3440x1440+0+0 (normal left inverted right x axis y axis) 819mm x 346mm
   3440x1440     99.98*+  84.96    74.98    59.97  
   1920x1080     60.00    59.94    50.00  
   1680x1050     59.95  
   1440x900      59.89  
   1440x576      50.00  
   1440x480      59.94  
   1280x1024     75.02    60.02  
   1280x960      60.00  
   1280x720      60.00    59.94    50.00  
   1152x864      75.00  
   1024x768      75.03    70.07    60.00  
   800x600       75.00    72.19    60.32    56.25  
   720x576       50.00  
   720x480       59.94  
   640x480       75.00    72.81    59.94    59.93  
DP-1 disconnected (normal left inverted right x axis y axis)

Check xoeg log file

$HOME/.local/share/xorg/Xorg.0.log