xrandr: Failed to get size of gamma for output default

[Duplino]

Im quite a noob. I followed all your steps, but I get the following output:

Start configuration
xrandr: Failed to get size of gamma for output default
xrandr: cannot find output "VIRTUAL1"
add resolution 1280x720
xrandr: Failed to get size of gamma for output default
warning: output VIRTUAL1 not found; ignoring
start display VIRTUAL1 to 1280x720
xrandr: Failed to get size of gamma for output default
Screen 0: minimum 640 x 480, current 640 x 480, maximum 640 x 480
default connected primary 640x480+0+0 0mm x 0mm
   640x480       73.00* 

Done, Check your VDL Monitor on System Setting > Display

And when I got to settings, I cant see the other display.
Any Ideas?

[dianariyanto]

give a try to change resolution on vdl-monitor.conf from 1280x720 to 640x480?

[dianariyanto]

i think, you cant add higer resolution than the default connected primary display. On your case, the default connected primary resolution is 640x480