I've a Lenovo T61 laptop with an Intel 965GM chipset and a 1280x800 panel. X server version is 1.3.0, intel driver is 2.1.0.  The laptop has a VGA port, but no S-Video or anything like that.

On X startup the intel driver detects two outputs: LVDS at 1280x800 and TV at 1027x768.  It exports this information to applications as two Xinerama screens (I hope I got my terminology right): screen 0 is +0+0-1024x768, screen 1 is +0+0-1280x800.  As a result GDM and GNOME panels are limited to the 1024x768 area of the desktop.  xrandr --output TV --off fixes this.

I would be happy with any of the following fixes:

  * make the intel driver correctly detect that I do not have a TV connected to my nonexistent TV out connection.

  * make the intel driver export the TV output as Xinerama screen 0 rather than 1, so that GDM and gnome panels would use the full size of the laptop panel.

By the way, if I try to disable the TV output in Xorg.conf with

  Section "Device"
    ...
    Option     "monitor-TV" "TVOutput"
  EndSection

  Section "Monitor"
    Identifier "TVOutput"
    Option     "Disable"    "true"
  EndSection

that works, but the command-line xrandr tool refuses to do anything and only prints an error message "Output TV is connected but has no modes" (I'm writing from memory so I may have got the phrasing wrong).