Enabling ATI TV Out in Linux

My brother asked me for help enabling TV out on an Ubuntu Maverick laptop. Googling finds lots of people having trouble with this so I have written about my solution. The big gotcha was you can't use S-Video without first disabling the VGA output.

jon@Ubuntu:~$ xrandr 
Screen 0: minimum 320 x 200, current 1024 x 768, maximum 8192 x 8192
VGA-0 connected 1024x768+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
   1360x768       59.8  
   1024x768       60.0* 
   800x600        60.3     56.2  
   848x480        60.0  
   640x480        59.9     59.9  
LVDS connected 1024x768+0+0 (normal left inverted right x axis y axis) 331mm x 207mm
   1280x800       59.9 +
   1280x720       59.9  
   1152x768       59.8  
   1024x768       59.9* 
   800x600        59.9  
   848x480        59.7  
   720x480        59.7  
   640x480        59.4  
S-video disconnected (normal left inverted right x axis y axis)

The suggested commands to try and enable S-Video are:

jon@Ubuntu:~$ xrandr --addmode S-video 1024x768
jon@Ubuntu:~$ xrandr --output S-video --mode 1024x768
xrandr: cannot find crtc for output S-video

When that does not work some people then try:

jon@Ubuntu:~$ xrandr --verbose --output S-video --set load_detection 1
X Error of failed request:  BadName (named color or font does not exist)
  Major opcode of failed request:  150 (RANDR)
  Minor opcode of failed request:  11 (RRQueryOutputProperty)
  Serial number of failed request:  31
  Current serial number in output stream:  31

It turns out that you must disable the VGA out before turning the S-Video on. We do not need VGA out so this solution is fine for us. The order of the commands is important but the warning from 'set load detection' can be ignored. Here is the recipe:

jon@Ubuntu:~$ xrandr --addmode S-video 1024x768
jon@Ubuntu:~$ xrandr --output VGA-0 --off
jon@Ubuntu:~$ xrandr --output S-video --set load_detection 1
jon@Ubuntu:~$ xrandr --output S-video --mode 1024x768