ATI
From MythTV Official Wiki
Supported by fglrx drivers
DVI to HDMI
Good support, mostly used DVI-HDMI cable to connect HDTV. Don't forget setup Underscan to remove black borders. Can be set that in /home/mythtv/.xinitrc:
/opt/bin/aticonfig --set-dispattrib=tmds2i,positionX:0 /opt/bin/aticonfig --set-dispattrib=tmds2i,positionY:0 /opt/bin/aticonfig --set-dispattrib=tmds2i,sizeX:1920 /opt/bin/aticonfig --set-dispattrib=tmds2i,sizeY:1080