[Mesa-dev] [PATCH] i965/blorp: Add also depth buffer to render cache

[Jason Ekstrand]

On Thu, Jan 19, 2017 at 12:40 PM, Francisco Jerez <currojerez at riseup.net>
wrote:

> "Pohjolainen, Topi" <topi.pohjolainen at gmail.com> writes:
>
> > On Thu, Jan 19, 2017 at 12:10:02PM -0800, Francisco Jerez wrote:
> >> Topi Pohjolainen <topi.pohjolainen at gmail.com> writes:
> >>
> >> > CC: Francisco Jerez <currojerez at riseup.net>
> >> > CC: Kenneth Graunke <kenneth at whitecape.org>
> >> > CC: Jason Ekstrand <jason at jlekstrand.net>
> >> > Signed-off-by: Topi Pohjolainen <topi.pohjolainen at intel.com>
> >> > ---
> >> >  src/mesa/drivers/dri/i965/genX_blorp_exec.c | 3 +++
> >> >  1 file changed, 3 insertions(+)
> >> >
> >> > diff --git a/src/mesa/drivers/dri/i965/genX_blorp_exec.c
> b/src/mesa/drivers/dri/i965/genX_blorp_exec.c
> >> > index 647a362..594bd5a 100644
> >> > --- a/src/mesa/drivers/dri/i965/genX_blorp_exec.c
> >> > +++ b/src/mesa/drivers/dri/i965/genX_blorp_exec.c
> >> > @@ -261,4 +261,7 @@ retry:
> >> >
> >> >     if (params->dst.enabled)
> >> >        brw_render_cache_set_add_bo(brw, params->dst.addr.buffer);
> >> > +
> >> > +   if (params->depth.enabled)
> >> > +      brw_render_cache_set_add_bo(brw, params->depth.addr.buffer);
> >>
> >> What about the stencil buffer?  Stencil texturing is likely to be
> >> unhappy unless you mark it as pending flush as well...
> >
> > As far as I know i965 only clears depth and color using blorp, stencil
> gets
> > cleared using meta. Blits in turn have it as destination.
> >
>
> That doesn't sound like a safe assumption to rely on looking forward if
> the blorp api already exposes support for stencil writes -- Tracking
> down the ultimate cause of a memory coherency bugs can be really hard,
> why make our future lives more intentionally difficult by introducing
> buggy corner cases like this?  The extra check is not going to hurt
> performance or cause any other harmful side effects unless stencil
> writes are used...
>

Agreed.  Let's stick it in there for stencil too.  I've got patches to
switch i965 over to blorp for depth/stencil blits.  I never landed them
because of what was most likely flushing bugs.  I'm hoping that you've
fixed those and I'll revive the patches.

Also, please make sure these fixes hit stable.

--Jason
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