Adding a non-detected modeline in ubuntu as default

I adapted the procedure I found here to make my old Samsung Syncmaster 192N work at its native resolution. It is running through an old projector on the ceiling, which I’m sure is what is breaking the autodetection.

cvt 1280 1024 75

That returned: # 1280×1024 74.90 Hz (CVT 1.31M4) hsync: 80.30 kHz; pclk: 138.75 MHz
Modeline “1280x1024_75.00″  138.75  1280 1368 1504 1728  1024 1027 1034 1072 -hsync +vsync

Added these lines to /etc/gdm/Init/Default:

xrandr –newmode “1280x1024_75.00″  138.75  1280 1368 1504 1728  1024 1027 1034 1072 -hsync +vsync

xrandr –addmode VGA-0 1280x1024_75.00

xrandr –output VGA-0 –mode 1280x1024_75.00

Now it starts out at the correct resolution at startup, regardless of the state of the projector.