[PATCH 04/11] xf86: Add PRIME flipping functions to ScreenRec

[Alex Goins]

Yeah, there's no open source implementation of these right now, but essentially
they just allow the source driver to do whatever specific setup necessary to
present to either of the two supplied shared buffers from the same headsurface,
as well as having presentation driven by PresentTrackedFlippingPixmap() as
opposed to some sort of internal mechanism.

It would probably be possible to implement (Start/Stop)PixmapTracking such that
multiple calls on the same mscreenpix with different shared pixmaps achieves
that behavior, but it would be less explicit and would probably result in some
unnecessary setup/teardown when switching to externally driven presentation on
the second call.

As of right now, I would expect multiple calls to StartPixmapTracking() with the
same mscreenpix but different shared pixmaps to result in two independently
driven shared pixmaps presenting from the same mscreenpix. I've been trying to
avoid tampering with the semantics of the old paths as much as possible.

Thanks,
Alex

On Tue, 8 Dec 2015, Michel Dänzer wrote:

> On 26.11.2015 11:39, Alex Goins wrote:
> > 
> > (Start/Stop)FlippingPixmapTracking are merely the double-buffered
> > equivalents of (Start/Stop)PixmapTracking, allowing the source driver to do
> > whatever setup and teardown necessary for presenting on the two shared
> > pixmaps.
> 
> AFAICT there's no implementation of these hooks in this series. Is it
> really necessary (or even worth) adding these hooks instead of just
> calling Start/StopPixmapTracking separately for the front and back pixmaps?
> 
> 
> -- 
> Earthling Michel Dänzer               |               http://www.amd.com
> Libre software enthusiast             |             Mesa and X developer
>