ATI Gatos
From MythTV Official Wiki
Recent Xorg has Gatos driver integrated.
In Ubuntu 8.10 following works at least with ATI Radeon 9200 card.
In /etc/X11/xorg.conf Device section add following lines
Option "ForceTVOut" "true"
Option "TVStandard" "pal"
install xvattr:
sudo apt-get install xvattr
Move X-Video (XV) from monitor to TV:
xvattr -a XV_CRTC -v 1