As my laptop is already running at 1024x768, I tried it with 800x600 and 640x480, neither of which had any effect - the resolution stayed the same
cjo20@clappy:~$ xrandr --output default --mode 800x600 cjo20@clappy:~$
cjo20@clappy:~$ xrandr --output default --mode 640x480 cjo20@clappy:~$
cjo20@clappy:~$ xrandr --output default --mode 1024x768 cjo20@clappy:~$
I got no X errors while running either of these commands.
As my laptop is already running at 1024x768, I tried it with 800x600 and 640x480, neither of which had any effect - the resolution stayed the same
cjo20@clappy:~$ xrandr --output default --mode 800x600
cjo20@clappy:~$
cjo20@clappy:~$ xrandr --output default --mode 640x480
cjo20@clappy:~$
cjo20@clappy:~$ xrandr --output default --mode 1024x768
cjo20@clappy:~$
I got no X errors while running either of these commands.