[compiz] AIGLX Support with nVidia 9625 Drivers

[David Reveman]

On Tue, 2006-09-26 at 19:06 +0200, wakko at generation.no wrote:
> On Tue, September 26, 2006 4:56 pm, David Reveman wrote:
> > On Mon, 2006-09-25 at 18:18 -0700, Soup Laddy wrote:
> >
> >> Something I've been worried about: I have an nVidia GeForce FX 5500
> >> card, and I'd been noticing some extreme tearing in XGL when
> >> rotating/manipulating the cube and moving around windows... a somewhat
> >> of a fix to that was to start XGL with __GL_SYNC_TO_VBLANK=1 ... but
> >> that then reduced performance. Is the tearing problem at all resolved
> >> with Compiz + AIGLX?
> >
> > Both xgl and aiglx implement indirect GL rendering. Hence all blits and
> > buffer swaps are done on the server side. If you force the driver to sync
> > to vblank (e.g. __GL_SYNC_TO_VBLANK), you usually force the server to
> > block and wait for the vblank. You get horrible performance this way as
> > this leaves the server very little time to process other X requests. I
> > have a patch that makes it possible for xgl to do buffer swaps in a
> > separate thread, hence making sure the main thread that is processing X
> > requests isn't blocked. However, last time I checked, there were no
> > drivers that could handle GL drawing from multiple threads to one drawable
> > properly.
> >
> > nvidia's new driver with GLX_EXT_tfp, support direct rendering. When using
> > this driver with direct rendering all blits and buffer swaps are done on
> > the client side by compiz itself. Blocking and waiting for vblank in
> > compiz will not stop the server from continuing to process X requests so
> > there's no performance impact on the server. The compiz code for doing
> > this is already in head and if you use the new nvidia driver with direct
> > rendering it should be turned on by default. There's a sync_to_vblank
> > option which allow you turn it off. Don't use __GL_SYNC_TO_VBLANK, compiz
> > is using GLX_SGI_video_sync to sync even partial screen updates to vblank.
> >
> >
> > -David
> >
> >
> > _______________________________________________
> > compiz mailing list compiz at lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/compiz
> >
> >
> 
> Does nvidia even use aiglx? doesn't nvidia have it's own accelerated
> indirect rendering architecture?

Correct, they have their own accelerated indirect rendering architecture
and they don't use aiglx. A lot of people seem to get this wrong.

-David