s/Don't disallow/Allow/ reads much, much better. The original wording made my head hurt. :)
On 11/19/2015 07:25 AM, Neil Roberts wrote: > Previously fast clear was disallowed on Gen9 for MSRTs with the claim > that some formats don't work but we didn't understand why. On further > investigation it seems the formats that don't work are the ones where > the render surface format is being overriden to a different format > than the one used for texturing. The one used for texturing is not > actually a renderable format. It arguably makes sense that the sampler > hardware doesn't handle the fast color correctly in these cases > because it shouldn't be possible to end up with a fast cleared surface > that is non-renderable. > > This patch changes the limitation to prevent fast clear for surfaces > where the format for rendering is overriden. > --- > src/mesa/drivers/dri/i965/brw_meta_fast_clear.c | 15 +++++++++++---- > 1 file changed, 11 insertions(+), 4 deletions(-) > > diff --git a/src/mesa/drivers/dri/i965/brw_meta_fast_clear.c > b/src/mesa/drivers/dri/i965/brw_meta_fast_clear.c > index 1f8bfdf..f2e894a 100644 > --- a/src/mesa/drivers/dri/i965/brw_meta_fast_clear.c > +++ b/src/mesa/drivers/dri/i965/brw_meta_fast_clear.c > @@ -48,6 +48,7 @@ > #include "brw_defines.h" > #include "brw_context.h" > #include "brw_draw.h" > +#include "brw_state.h" > #include "intel_fbo.h" > #include "intel_batchbuffer.h" > > @@ -549,11 +550,17 @@ brw_meta_fast_clear(struct brw_context *brw, struct > gl_framebuffer *fb, > if (brw->gen < 7) > clear_type = REP_CLEAR; > > - /* Certain formats have unresolved issues with sampling from the MCS > - * buffer on Gen9. This disables fast clears altogether for MSRTs until > - * we can figure out what's going on. > + /* If we're mapping the render format to a different format than the > + * format we use for texturing then it is a bit questionable whether it > + * should be possible to use a fast clear. Although we only actually > + * render using a renderable format, without the override workaround it > + * wouldn't be possible to have a non-renderable surface in a fast > clear > + * state so the hardware probably legitimately doesn't need to support > + * this case. At least on Gen9 this really does seem to cause problems. > */ > - if (brw->gen >= 9 && irb->mt->num_samples > 1) > + if (brw->gen >= 9 && > + brw_format_for_mesa_format(irb->mt->format) != > + brw->render_target_format[irb->mt->format]) > clear_type = REP_CLEAR; > > if (irb->mt->fast_clear_state == INTEL_FAST_CLEAR_STATE_NO_MCS) > _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
