[Mesa3d-dev] Re: [Dri-devel] New tdfx driver, locking, small device driver changes

[Nathan H. <na...@ma...>]

On Mon, Oct 09, 2000 at 01:55:53PM -0600, Keith Whitwell wrote:
> 
> One potential problem with this is that in fallback cases we will hold the
> hardware lock for the time it takes to render an entire vertex buffer of
> triangles, one spanline at a time.  I propose to get around this by 'flashing'
> the lock in the spanline and pixel functions, eg:
> 
> 	UNLOCK_HARDWARE(fxMesa);
> 	LOCK_HARDWARE(fxMesa);
> 	...
> 
> To allow a (tiny) window for the X server or other clients to grab the lock.  

Instead of putting the UNLOCK/LOCK pairs inside the span functions, and
having LOCK/UNLOCK around the slow fallbacks, how about having the slow 
fallback default to nolock but with LOCK/UNLOCK around each call to the
span functions.

The cliprects would be reworked (if necessary) around each span, inside
the LOCK/UNLOCK pair and just before drawing the span.

The other option is to extend the X server for two forms of lock: 1 for
changing the cliprects and 1 for everything else. Then you can lock the
cliprects around the whole fallback and unlock everything else with the
"flashing" concept.