On Fri, Nov 13, 2015 at 10:23:20PM +0100, Neil Roberts wrote: > There are currently a bunch of formats that behave strangely when > sampling the cleared color from the MCS buffer on SKL. They seem to > mostly be formats that don't have an alpha component, although it's > not all of them, and we haven't yet found anything in the specs which > would explain this. For now to be on the safe side this patch just > disables fast clears for MSRTs on SKL altogether. The assumption is > that clears are probably more likely to be used in single-sampled > applications anyway so we can at least get them working and we can > enable MSRTs later once we understand the problem better. > --- > > If we go with this patch we could remove the explicit check for the > half-float intensity and luminance formats as well. > > src/mesa/drivers/dri/i965/brw_meta_fast_clear.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > 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 dc085ba..85576a8 100644 > --- a/src/mesa/drivers/dri/i965/brw_meta_fast_clear.c > +++ b/src/mesa/drivers/dri/i965/brw_meta_fast_clear.c > @@ -524,6 +524,13 @@ 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 (brw->gen >= 9 && irb->mt->num_samples > 1) > + clear_type = REP_CLEAR; > + > if (irb->mt->fast_clear_state == INTEL_FAST_CLEAR_STATE_NO_MCS) > clear_type = REP_CLEAR; >
(Perhaps "Disable fast clears..." is a misleading title because it doesn't really disable them. A note that this patch should have no functional effect other than perhaps receiving fewer perf_debug messages on SKL+ could be helpful to being looking into backports). Reviewed-by: Ben Widawsky <benjamin.widaw...@intel.com> _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
