Updates to GLX_EXT_texture_from_pixmap

[Eric Anholt]

On Tue, 2006-04-04 at 09:06 +0200, Michel Dänzer wrote:
> On Mon, 2006-04-03 at 15:32 -0800, James Jones wrote:
> > 
> > I have limited knowledge of X internals though.  Should it turn out 
> > that there exists or can be implemented an easy way for drivers to 
> > cause the server to take a driver-managed lock before rendering, 
> 
> AFAIK EXA calls the driver before and after each rendering operation to
> or from a pixmap, accelerated or not.

There a single call for before/after any rendering, though people have
often interpreted PrepareAccess()/FinishAccess() to be that.  Those two
are only for CPU reading/writing to a pixmap.  However, you can stick
your wrapping in each Prepare<Op>()/Done<Op>(), plus UTS() and DFS(),
for accelerated stuff.  I've done this in fakexa, where I have to do a
little bit of extra work to have pixmaps prepped for rendering with fb
in the "accelerated" cases.

Of course, I think taking and dropping the DRI lock for each operation
would probably be rather harsh.  Currently we're probably too
coarse-grained, where we grab during WakeupHandler and drop at
BlockHandler.  I suspect there's a happy medium with picking up the lock
before rendering, and dropping the lock on a timer or BlockHandler,
whichever comes first.  Of course, that doesn't take care of window tree
update issues, which I haven't thought through enough to say they
wouldn't be an issue.

ObBug #5632

-- 
Eric Anholt                     anholt at FreeBSD.org
eric at anholt.net                 eric.anholt at intel.com
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