From 5dfb4dbc0583d2593e36f7eb27c77b81680db848 Mon Sep 17 00:00:00 2001 From: Neil Roberts Date: Mon, 16 Nov 2015 14:03:11 +0100 Subject: [PATCH] i965: Prevent fast clears for MSRTs on SKL 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 prevents fast clears for MSRTs on SKL altogether so that when fast clears are eventually enabled it will only be for single-sampled surfaces. 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. This patch should have no functional effect other than perhaps receiving fewer perf_debug messages on SKL+. v2: Improve the commit message to avoid saying the patch disables fast clears because it will be merged before fast clears are enabled for any surfaces so it doesn't actually disable anything. Reviewed-by: Ben Widawsky Reviewed-by: Chad Versace --- 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 12e7c32e424..211c0a44162 100644 --- a/src/mesa/drivers/dri/i965/brw_meta_fast_clear.c +++ b/src/mesa/drivers/dri/i965/brw_meta_fast_clear.c @@ -447,6 +447,13 @@ 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; -- 2.30.2