drm/amdgpu: don't invalidate caches in RELEASE_MEM, only do the writeback

This RELEASE_MEM use has the Release semantic, which means we should write
back but not invalidate. Invalidations only make sense with the Acquire
semantic (ACQUIRE_MEM), or when RELEASE_MEM is used to do the combined
Acquire-Release semantic, which is a barrier, not a fence.

The undesirable side effect of doing invalidations for the Release semantic
is that it invalidates caches while shaders are running, because the Release
can execute in the middle of the next IB.

UMDs should use ACQUIRE_MEM at the beginning of IBs. Doing cache
invalidations for a fence (like in this case) doesn't do anything
for correctness.

Signed-off-by: Marek Olšák <marek.olsak@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/amdgpu/gfx_v10_0.c b/drivers/gpu/drm/amd/amdgpu/gfx_v10_0.c
index 4b2601a5e969d24ecf4e7d95a4c8d626cdc2fdbc..ee41d5592c5113fb515ee21f59585b41cd8f2c07 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/gfx_v10_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/gfx_v10_0.c
@@ -4285,11 +4285,7 @@ static void gfx_v10_0_ring_emit_fence(struct amdgpu_ring *ring, u64 addr,
        amdgpu_ring_write(ring, PACKET3(PACKET3_RELEASE_MEM, 6));
        amdgpu_ring_write(ring, (PACKET3_RELEASE_MEM_GCR_SEQ |
                                 PACKET3_RELEASE_MEM_GCR_GL2_WB |
-                                PACKET3_RELEASE_MEM_GCR_GL2_INV |
-                                PACKET3_RELEASE_MEM_GCR_GL2_US |
-                                PACKET3_RELEASE_MEM_GCR_GL1_INV |
-                                PACKET3_RELEASE_MEM_GCR_GLV_INV |
-                                PACKET3_RELEASE_MEM_GCR_GLM_INV |
+                                PACKET3_RELEASE_MEM_GCR_GLM_INV | /* must be set with GLM_WB */
                                 PACKET3_RELEASE_MEM_GCR_GLM_WB |
                                 PACKET3_RELEASE_MEM_CACHE_POLICY(3) |
                                 PACKET3_RELEASE_MEM_EVENT_TYPE(CACHE_FLUSH_AND_INV_TS_EVENT) |