Updates to GLX_EXT_texture_from_pixmap

[Michel Dänzer]

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.

> I'm once again going to propose more or less the same compromise:  
> We could write a separate GLX extension to do the locking.  This 
> would still have the advantage of keeping EXT_texture_from_pixmap 
> as simple and lean as possible and provide the semantics & 
> performance you're looking for.  To support such an extension, I'd 
> still need to be convinced it was reasonable to implement such a 
> lock and we would have to measure a large enough performance hit 
> from the currently proposed methods to justify it.  
> 
> Note that if we agree on this separate extension approach in any 
> form, we could have a period where a completely specified version 
> of texture_from_pixmap is available and implemented in several 
> drivers, and various developers could actually peform tests to 
> determine exactly what kind of performance enhancements and locking 
> semantics are needed.  They can then be added without breaking the 
> existing extension.  It would be much more painful to remove 
> unproven locking semantics found to be unreasonable or inadequit 
> (for whatever reason) from a finished, shipping extension.

I agree, and it's my impression that so does pretty much everybody else
except Deron.


-- 
Earthling Michel Dänzer      |     Debian (powerpc), X and DRI developer
Libre software enthusiast    |   http://svcs.affero.net/rm.php?r=daenzer