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

[John P Poet]

On 11/6/06, Doug Larrick <doug at parkercat.org> wrote:
> John P Poet wrote:
> > I have been using OpenGL vsync ever since Doug added it to Myth.
> >
> > I just did a fresh install of FC6 on my frontend machine.  Ever since
> > doing so, enabling OpenGL vsync causes a minor but consistant stutter
> > of HD playback.  It is basically like a micro-second pause every
> > second.  If I turn off OpenGL vsync, the problem goes away.
> >
> > Has anyone else noticed this?  If so, has anyone determine whether it
> > is a Xorg 7.1 or an nVidia driver problem?  I tried going back on
> > version of the nVidia driver, but that had no effect.  Unfortunately,
> > I don't remember exactly which version of the nVidia driver I was
> > running before.
>
> I'm running Xorg 7.1 (Debian) and nvidia 8776 on my main box with an
> FX5200; no issues.
>
> 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.
>
> If I turn on something like Compiz things go to pot: I see maybe 10 fps
> (that is, all the frames are displayed by Myth but only some of them
> make it to the actual screen).  Not altogether surprising.
>
> You might measure your CPU consumption; if it's too high you'll see the
> behavior you're describing as the non-realtime threads get starved.
>
> -Doug

Thanks Doug.  I will play around with it some more.

John