[Mesa-dev] [PATCH 1/9] st/mesa: always prefer pipe->clear over clear_with_quad

[Jose Fonseca]

If this is such a corner case, that's not worth the diligence, then I think it might be better to drop the change.

If it was just software rendering (llvmpipe) I wouldn't mind, as bottlenecks are elsewhere anyway.  My concern is more of principle here: I'm assuming there is other hardware we care about that has interleaved depth stencil (*), and whatever the separate depth-stencil hardware has to gain with this change, the former stands to lose.  And this is the sort of precedent what I want to prevent.

If it was regressing hardware nobody cares for the sake of hardware that people do, I'd be fine.  What I really don't want is developer A commiting a change that makes driver X faster but Y slower, then developer B commits a change that makes Y faster and X slower, and we go around in circles instead of moving all forward.

But if I'm wrong -- nobody else cares -- I won't object further.

Jose

(*) I only recall AMD having them separate, so I assume e.g., NVIDIA has them interleaved.  And I'm not sure if all have use the fast clear optimization.

----- Original Message -----
> José, is it really worth adding a new cap? The only way to hit both
> pipe->clear and clear_with_quad for depth and stencil, respectively,
> is to have a partial stencil writemask.
> 
> Marek
> 
> On Fri, Dec 13, 2013 at 5:46 PM, Jose Fonseca <jfonseca at vmware.com> wrote:
> >
> > So, if this provides a significant performance difference, then I think the
> > only option to have everybody happy is to have cap to choose the optimal
> > behavior
>