$ xrandr
xrandr: Failed to get size of gamma for output default
Screen 0: minimum 640 x 480, current 1024 x 768, maximum 1024 x 768
default connected 1024x768+0+0 0mm x 0mm
   1024x768       61.0*
   1024x512        0.0
   800x600        61.0
   848x480         0.0
   800x480         0.0
   640x480        60.0