How To Reduce/Eliminate Horizontal Tearing

[Nikos Chantziaras]

Keith Packard wrote:
> On Wed, 2008-12-10 at 23:14 -0500, Nick Nobody wrote:
>> Hello,
>>
>> I'm using Ubuntu 8.10 with a GM945 (at 1920x1080) for my media center PC.
>> The problem I'm running into is a bunch of horizontal tearing on higher
>> resolution videos (720p or greater). From what I can tell it's not a CPU
>> limitation but rather something related to the graphics card...
>>
>> Are there any options that I can enable in my xorg.conf to help
>> reduce/eliminate this tearing? Or is this simply a hardware limitation?
>> Can XvMC somehow help me here?
> 
> There aren't any options at this point, but I'm wondering -- is this
> full-screen? If we made full-screen Xv operations block until vblank
> (which would lock up the X server), would that be an acceptable option?
> 
> It's actually very easy to do, just stick a 'wait for vblank' command
> into the ring right before the 'copy the new picture' command in the Xv
> extension code. It's just annoying when you're watching a tiny movie and
> your whole session stops responding.

That would be just a temporary solution with too many problems (since I 
assume a real solution will be in DRI2?)  The OpenGL method with VSync 
works quite well.