From e6fb3ba03798fc2550bdb5ec6651690a34ac3509 Mon Sep 17 00:00:00 2001 From: Kenneth Graunke Date: Wed, 24 Apr 2024 00:43:16 -0700 Subject: [PATCH] isl: Set MOCS to uncached for Gfx12.0 blitter sources/destinations We were accidentally leaving XY_BLOCK_COPY_BLT's Source and Destination MOCS fields set to 0 (Error: Reserved for Non-Use) on Gfx12.0 systems. This was causing assert fails in debug builds, since we try to ensure that we don't do that. In theory, MOCS 0 is supposed to be equivalent to MOCS 2 (all the caching), but...we probably ought to use MOCS 3 (uncached). Every Gfx12.5+ platform requires it, so although there isn't a note about Gfx12.0 needing that, it's possible that it does. We're currently only using the blitter for DRI PRIME blits on Gfx12.0, anyway, and I think we're flushing all the caches regardless. This bug was somewhat obscure to hit: - You need a hybrid graphics system with Gfx12.0 and some other GPU - You have to be using "reverse PRIME", i.e. rendering on the integrated GPU and displaying on the discrete one. This is not the common case. - You have to be using a debug build. No observable performance delta in GfxBench5 Car Chase (an arbitrary program) when rendering on Alderlake GT1 and displaying on an Arc A770. Fixes: 194afe84163 ("anv/iris/blorp: use the right MOCS values for each engine") Reviewed-by: Lionel Landwerlin Reviewed-by: Rohan Garg Part-of: --- src/intel/isl/isl.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/src/intel/isl/isl.c b/src/intel/isl/isl.c index c0b154cd6c5..9902452e51c 100644 --- a/src/intel/isl/isl.c +++ b/src/intel/isl/isl.c @@ -175,6 +175,8 @@ isl_device_setup_mocs(struct isl_device *dev) dev->mocs.external = 5 << 1; /* UC */ dev->mocs.uncached = 1 << 1; + dev->mocs.blitter_dst = 1 << 1; + dev->mocs.blitter_src = 1 << 1; } else { /* TC=1/LLC Only, LeCC=1/UC, LRUM=0, L3CC=3/WB */ dev->mocs.external = 61 << 1; @@ -185,6 +187,10 @@ isl_device_setup_mocs(struct isl_device *dev) /* L1 - HDC:L1 + L3 + LLC */ dev->mocs.l1_hdc_l3_llc = 48 << 1; + + /* Uncached */ + dev->mocs.blitter_dst = 3 << 1; + dev->mocs.blitter_src = 3 << 1; } /* Protected is just an additional flag. */ dev->mocs.protected_mask = 1 << 0;