[Mesa-dev] [PATCH 04/10] i965/skl: skip fast clears for certain surface formats

Ben Widawsky ben at bwidawsk.net
Wed Oct 14 10:32:34 PDT 2015


On Wed, Oct 14, 2015 at 01:10:23PM +0200, Neil Roberts wrote:
> It would be nice if you could give some indication of where this list of
> formats came from.
> 
> Unless we expect the list to change with future generations, maybe it
> would be better to make it a static const table? It's a shame to grow
> the context size unnecessarily.
> 
> Regards,
> - Neil
> 

You are correct, I should have referenced it. It is in the section titled
"Render Target Surface Types [SKL+] - Surface Formats for Render Target Messages
[SKL+]"

The supported formats do change, for now we could certainly assume that SKL is
the base set and future GENs add things.

> Ben Widawsky <benjamin.widawsky at intel.com> writes:
> 
> > Initially I had this planned as a patch to be squashed in to the enabling patch
> > because there is no point enabling fast clears without this. However, Chad
> > merged a patch which disables fast clears on gen9 explicitly, and so I can hide
> > this behind the revert of that patch. This is a nice I really wanted this patch
> > as a distinct patch for review. This is a new, weird, and poorly documented
> > restriction for SKL. (In fact, I am still not 100% certain the restriction is
> > entirely necessary, but there are around 30 piglit regressions without this).
> >
> > SKL adds compressible render targets and as a result mutates some of the
> > programming for fast clears and resolves. There is a new internal surface type
> > called the CCS. The old AUX_MCS bit becomes AUX_CCS_D. "The Auxiliary surface is
> > a CCS (Color Control Surface) with compression disabled or an MCS with
> > compression enabled, depending on number of multisamples. MCS (Multisample
> > Control Surface) is a special type of CCS."
> >
> > Signed-off-by: Ben Widawsky <ben at bwidawsk.net>
> > ---
> >  src/mesa/drivers/dri/i965/brw_context.h         |  1 +
> >  src/mesa/drivers/dri/i965/brw_surface_formats.c | 27 +++++++++++++++++++++++++
> >  src/mesa/drivers/dri/i965/gen8_surface_state.c  |  8 ++++++--
> >  src/mesa/drivers/dri/i965/intel_mipmap_tree.c   |  3 +++
> >  4 files changed, 37 insertions(+), 2 deletions(-)
> >
> > diff --git a/src/mesa/drivers/dri/i965/brw_context.h b/src/mesa/drivers/dri/i965/brw_context.h
> > index e59478a..32b8250 100644
> > --- a/src/mesa/drivers/dri/i965/brw_context.h
> > +++ b/src/mesa/drivers/dri/i965/brw_context.h
> > @@ -1546,6 +1546,7 @@ struct brw_context
> >  
> >     uint32_t render_target_format[MESA_FORMAT_COUNT];
> >     bool format_supported_as_render_target[MESA_FORMAT_COUNT];
> > +   bool losslessly_compressable[MESA_FORMAT_COUNT];
> >  
> >     /* Interpolation modes, one byte per vue slot.
> >      * Used Gen4/5 by the clip|sf|wm stages. Ignored on Gen6+.
> > diff --git a/src/mesa/drivers/dri/i965/brw_surface_formats.c b/src/mesa/drivers/dri/i965/brw_surface_formats.c
> > index 97fff60..d706ecc 100644
> > --- a/src/mesa/drivers/dri/i965/brw_surface_formats.c
> > +++ b/src/mesa/drivers/dri/i965/brw_surface_formats.c
> > @@ -693,6 +693,33 @@ brw_init_surface_formats(struct brw_context *brw)
> >        }
> >     }
> >  
> > +   if (brw->gen >= 9) {
> > +      brw->losslessly_compressable[MESA_FORMAT_RGBA_FLOAT32] = true;
> > +      brw->losslessly_compressable[MESA_FORMAT_RGBA_SINT32] = true;
> > +      brw->losslessly_compressable[MESA_FORMAT_RGBA_UINT32] = true;
> > +      brw->losslessly_compressable[MESA_FORMAT_RGBA_UNORM16] = true;
> > +      brw->losslessly_compressable[MESA_FORMAT_RGBA_SNORM16] = true;
> > +      brw->losslessly_compressable[MESA_FORMAT_RGBA_SINT16] = true;
> > +      brw->losslessly_compressable[MESA_FORMAT_RGBA_UINT16] = true;
> > +      brw->losslessly_compressable[MESA_FORMAT_RGBA_FLOAT16] = true;
> > +      brw->losslessly_compressable[MESA_FORMAT_RG_FLOAT32] = true;
> > +      brw->losslessly_compressable[MESA_FORMAT_RG_SINT32] = true;
> > +      brw->losslessly_compressable[MESA_FORMAT_RG_UINT32] = true;
> > +      brw->losslessly_compressable[MESA_FORMAT_RGBX_FLOAT16] = true;
> > +      brw->losslessly_compressable[MESA_FORMAT_B8G8R8A8_UNORM] = true;
> > +      brw->losslessly_compressable[MESA_FORMAT_R8G8B8A8_UNORM] = true;
> > +      brw->losslessly_compressable[MESA_FORMAT_R8G8B8A8_SNORM] = true;
> > +      brw->losslessly_compressable[MESA_FORMAT_RGBA_SINT8] = true;
> > +      brw->losslessly_compressable[MESA_FORMAT_RGBA_UINT8] = true;
> > +      brw->losslessly_compressable[MESA_FORMAT_RG_SINT16] = true;
> > +      brw->losslessly_compressable[MESA_FORMAT_RG_UINT16] = true;
> > +      brw->losslessly_compressable[MESA_FORMAT_RG_FLOAT16] = true;
> > +      brw->losslessly_compressable[MESA_FORMAT_R_UINT32] = true;
> > +      brw->losslessly_compressable[MESA_FORMAT_R_SINT32] = true;
> > +      brw->losslessly_compressable[MESA_FORMAT_R_FLOAT32] = true;
> > +      brw->losslessly_compressable[MESA_FORMAT_B8G8R8X8_UNORM] = true;
> > +   }
> > +
> >     /* We will check this table for FBO completeness, but the surface format
> >      * table above only covered color rendering.
> >      */
> > diff --git a/src/mesa/drivers/dri/i965/gen8_surface_state.c b/src/mesa/drivers/dri/i965/gen8_surface_state.c
> > index 995b4dd..b19b492 100644
> > --- a/src/mesa/drivers/dri/i965/gen8_surface_state.c
> > +++ b/src/mesa/drivers/dri/i965/gen8_surface_state.c
> > @@ -243,8 +243,10 @@ gen8_emit_texture_surface_state(struct brw_context *brw,
> >         * "When Auxiliary Surface Mode is set to AUX_CCS_D or AUX_CCS_E, HALIGN
> >         *  16 must be used."
> >         */
> > -      if (brw->gen >= 9 || mt->num_samples == 1)
> > +      if (brw->gen >= 9 || mt->num_samples == 1) {
> >           assert(mt->halign == 16);
> > +         assert(mt->num_samples || brw->losslessly_compressable[mt->format] == true);
> > +      }
> >     }
> >  
> >     const uint32_t surf_type = translate_tex_target(target);
> > @@ -488,8 +490,10 @@ gen8_update_renderbuffer_surface(struct brw_context *brw,
> >         * "When Auxiliary Surface Mode is set to AUX_CCS_D or AUX_CCS_E, HALIGN
> >         *  16 must be used."
> >         */
> > -      if (brw->gen >= 9 || mt->num_samples == 1)
> > +      if (brw->gen >= 9 || mt->num_samples == 1) {
> >           assert(mt->halign == 16);
> > +         assert(mt->num_samples || brw->losslessly_compressable[mt->format] == true);
> > +      }
> >     }
> >  
> >     uint32_t *surf = allocate_surface_state(brw, &offset, surf_index);
> > diff --git a/src/mesa/drivers/dri/i965/intel_mipmap_tree.c b/src/mesa/drivers/dri/i965/intel_mipmap_tree.c
> > index 32f0ff7..f108b75 100644
> > --- a/src/mesa/drivers/dri/i965/intel_mipmap_tree.c
> > +++ b/src/mesa/drivers/dri/i965/intel_mipmap_tree.c
> > @@ -265,6 +265,9 @@ intel_miptree_supports_non_msrt_fast_clear(struct brw_context *brw,
> >     if (!brw->format_supported_as_render_target[mt->format])
> >        return false;
> >  
> > +   if (brw->gen >= 9 && !brw->losslessly_compressable[mt->format])
> > +      return false;
> > +
> >     return true;
> >  }
> >  
> > -- 
> > 2.6.1
> >
> > _______________________________________________
> > mesa-dev mailing list
> > mesa-dev at lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/mesa-dev

-- 
Ben Widawsky, Intel Open Source Technology Center


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