[PATCH 4/5] glx: Implement GLX_PRESERVED_CONTENTS drawable attribute

[Adam Jackson]

On Mon, 2013-02-25 at 23:10 -0800, Eric Anholt wrote:
> Adam Jackson <ajax at redhat.com> writes:
> 
> > We back pixmaps with pbuffers so they're never actually clobbered, so
> > we're really just recording the value passed in at create time so that
> > you get the same thing when you query.
> 
> I guess I'm not clear on this one why we wouldn't just always say that
> we always have a preserved buffer -- we always behave that way, right?

We do always behave that way.

I guess it depends whether we take a loose or strict interpretation of
the spec.  It doesn't say the result of the query must match the value
at creation, and it does say that unpreserved buffers _may_ lose their
contents at any time, but it doesn't say that the server is allowed to
silently promote GLX_PRESERVED_CONTENTS to True.

Still, I doubt there's a client in the world that would notice, and it's
certainly less code.  v2 to follow.

- ajax