I was successfully using xrandr to extend my desktop in my work place with this little "script".
#!/bin/sh
xrandr --newmode 1920x1080 220.64 1920 2056 2264 2608 1080 1081 1084 1128 -HSync +Vsync
xrandr --addmode VGA 1920x1080
xrandr --output VGA --mode 1920x1080
Everything was going well till one day that magically stop working. When I try to use it. I just get this message.
X Error of failed request: BadName (named color or font does not exist)
The laptop display resizes in a strange way, but nothing happens with the extended monitor.
I've restored gnome desktop default config. I changed the font config, I tried with other layouts and monitors, but always occur the same.
Have you tried using a different name for that mode? I was getting this error and tried using the name "1080p" (e.g. xrandr --newmode "1080p"...) instead of the "1920x1080" name that I usually use and it worked. I'm not sure what's causing the error, as the 1920x1080 mode isn't even listed by xrandr, nor can it be removed via --rmmode, but creating a new mode with a different name seemed to work for me.