I've been trying to set up an external monitor for a bit, finally got it mostly working except the resolution is off. My monitor's native res is 1600×900, which I finally got to show up in xrandr:
user:~$ xrandr
xrandr: Failed to get size of gamma for output default
Screen 0: minimum 640 x 480, current 1024 x 768, maximum 1600 x 900
default connected 1024x768+0+0 0mm x 0mm
1024x768 0.0*
800x600 0.0
640x480 0.0
1600x900 59.9
However when I try to change the resolution I get the following error:
user:~$ xrandr --output default --mode 1600x900
xrandr: Failed to get size of gamma for output default
xrandr: Configure crtc 0 failed
Best Answer
I found that problem with ATI video drivers, with deactivated driver all works.
Use
to determine your ctrtc number? And try correct output syntax, e.g.:
other outputs: