[mythtv-users] OpenGL vsync broken on Xorg 7.1 or latest nVidia driver?

John P Poet jppoet at gmail.com
Sun Feb 18 23:48:53 UTC 2007

On 2/18/07, Doug Larrick <doug at parkercat.org> wrote:
> John P Poet wrote:
> >> I'm running Xorg 7.1 and nvidia 9625 (beta) on my dev box with an
> >> MX440 and have my choice between tearing (which I'd never seen from
> >> any nvidia driver ever before) or high CPU usage (too high to watch
> >> HD), depending on the sync-to-vblank settings in nvidia-settings.
> >
> > I was not even doing a "nvidia-settings --load-config-only", so I kind
> > of discounted this, but you are right.
> >
> > If I have "0/SyncToVBlank=0" it smooths-out the playback, and the
> > stuttering is gone -- but I end up with MAJOR tearing.
> >
> > If I do not load the nvidia-settings at all, or have
> > "0/SyncToVBlank=1", then I do not get the tearing, but have the
> > stuttering problem.
> >
> > My CPU usage does get high with HD material, but is low with SD
> > material.  I have the stuttering problem with SD material too.
> >
> > This is with nVidia driver 9746 on a FX5700LE.
> >
> > I guess I will try an older nVidia driver.
> Hi John,
> Just getting back from vacation and saw your note...
> Have you played around with 'Option "UseEvents" "true"' in your
> xorg.conf?  With a new enough nVidia driver the default video out method
> changed from Xv overlay to video texture (just like the newer cards,
> which can't do overlay at all), and this new option is necessary to get
> it working nicely again.
> As far as the debug statements in vsync.cpp -- yeah, that code got
> reworked fairly recently I think, and whoever did it probably didn't fix
> up the debug statements.
> -Doug

Thanks Doug.

Actually, the magic setting which fixed it for me, was:

Section "Extensions"
    Option "Composite" "Disable"


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