[Mesa-dev] [PATCH 7/7] radeonsi: fix a compute shader hang with big threadgroups on SI & CI

[Marek Olšák]

From: Marek Olšák <marek.olsak at amd.com>

ported from Vulkan

Cc: 12.0 <mesa-stable at lists.freedesktop.org>
---
 src/gallium/drivers/radeonsi/si_compute.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/src/gallium/drivers/radeonsi/si_compute.c b/src/gallium/drivers/radeonsi/si_compute.c
index 2f7e172..f19e830 100644
--- a/src/gallium/drivers/radeonsi/si_compute.c
+++ b/src/gallium/drivers/radeonsi/si_compute.c
@@ -443,6 +443,21 @@ static void si_launch_grid(
 	struct si_context *sctx = (struct si_context*)ctx;
 	struct si_compute *program = sctx->cs_shader_state.program;
 	int i;
+	/* HW bug workaround when CS threadgroups > 256 threads and async
+	 * compute isn't used, i.e. only one compute job can run at a time.
+	 * If async compute is possible, the threadgroup size must be limited
+	 * to 256 threads on all queues to avoid the bug.
+	 * Only SI and certain CIK chips are affected.
+	 */
+	bool cs_regalloc_hang =
+		(sctx->b.chip_class == SI ||
+		 sctx->b.family == CHIP_BONAIRE ||
+		 sctx->b.family == CHIP_KABINI) &&
+		info->block[0] * info->block[1] * info->block[2] > 256;
+
+	if (cs_regalloc_hang)
+		sctx->b.flags |= SI_CONTEXT_PS_PARTIAL_FLUSH |
+				 SI_CONTEXT_CS_PARTIAL_FLUSH;
 
 	si_decompress_compute_textures(sctx);
 
@@ -493,6 +508,9 @@ static void si_launch_grid(
 	sctx->b.num_compute_calls++;
 	if (sctx->cs_shader_state.uses_scratch)
 		sctx->b.num_spill_compute_calls++;
+
+	if (cs_regalloc_hang)
+		sctx->b.flags |= SI_CONTEXT_CS_PARTIAL_FLUSH;
 }
 
 
-- 
2.7.4