Fun with modelines

[the_riviera_kid]

I didn't expect that getting my MythTV box to talk to my new TV would be easy. This is lucky, or I would have been very disappointed.

TV out via composite works as well as ever at 800x600. I haven't played further with this.

VGA out works only in certain modes. To make things more interesting, the TV won't talk EDID over VGA to my GeForce2. I'm not sure which end is the culprit here. The TV manual claims that it will only accept 640x480, 800x600 and 1024x768, but it lies.

• The Ubuntu boot splash screen displays beautifully in a mode the TV classifies as SXGA.
• Within X via nvidia 800x600 works perfectly if the HSync an VRefresh rates are correctly set in xorg.conf. Otherwise the fallback is 640x480 (which also works perfectly).
• 1280x720 sort of displays via nvidia. There's huge overscan and the colour is completely wrong (my blue background displays green). Furthermore, the TV disables its 'PC mode' menus, so I can't adjust the colour or correct the overscan at the TV side. I'm not sure that this is the television at fault, because:
• During failsafe testing it looks like the vesa driver will drive 1280x720 correctly. I haven't been able to replicate this in an xorg.conf (the result is "no valid modes found for 1280x720", regardless of the variations in modeline I try).
• 1024x768 works though vesa but not nvidia ("No valid modes found..."). Unfortunately video playback using vesa is so choppy as to be unwatchable.
• I haven't done much testing with 'nv' yet, as trying to use nv after nvidia causes the system to lock up.
  

My limited HDMI testing has been done using the DVI out of what I think is a GeForce 4400 on a separate machine. Its xorg.conf is set to use 13??x768, and I don't have root access to change this. This mode gives me "No valid modes found" and the fallback is a surprising 720x480, which works perfectly with a little overscan. VGA out doesn't work on this machine with the current xorg.conf.
I can get useful EDID information out of this DVI set-up. However, the only two modes the TV claims to support are 1920x540 and 720x576. I can't actually try these out on this DVI machine, but I can copy the corresponding modelines over to my MythTV box.
1920x540 won't work, because the GeForce2 doesn't support interlaced modes.
720x576 'works' via nvidia in the same way that 1280x720 did.

The next step will be to try a DVI capable graphics card in my MythTV box (where I have control to play with modelines and other xorg.conf settings).