[Mesa-dev] [PATCH 6/8] radeonsi: fix VM faults due NULL internal const buffers on CIK

[Marek Olšák]

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

They are harmless, but the interrupts do decrease performance.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=97039

Cc: 12.0 <mesa-stable at lists.freedesktop.org>
---
 src/gallium/drivers/radeonsi/si_pipe.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/src/gallium/drivers/radeonsi/si_pipe.c b/src/gallium/drivers/radeonsi/si_pipe.c
index 62b62db..2669c7b 100644
--- a/src/gallium/drivers/radeonsi/si_pipe.c
+++ b/src/gallium/drivers/radeonsi/si_pipe.c
@@ -244,36 +244,45 @@ static struct pipe_context *si_create_context(struct pipe_screen *screen,
 	if (sctx->blitter == NULL)
 		goto fail;
 	sctx->blitter->draw_rectangle = r600_draw_rectangle;
 
 	sctx->sample_mask.sample_mask = 0xffff;
 
 	/* these must be last */
 	si_begin_new_cs(sctx);
 	r600_query_init_backend_mask(&sctx->b); /* this emits commands and must be last */
 
-	/* CIK cannot unbind a constant buffer (S_BUFFER_LOAD is buggy
-	 * with a NULL buffer). We need to use a dummy buffer instead. */
+	/* CIK cannot unbind a constant buffer (S_BUFFER_LOAD doesn't skip loads
+	 * if NUM_RECORDS == 0). We need to use a dummy buffer instead. */
 	if (sctx->b.chip_class == CIK) {
 		sctx->null_const_buf.buffer = pipe_buffer_create(screen, PIPE_BIND_CONSTANT_BUFFER,
 								 PIPE_USAGE_DEFAULT, 16);
 		if (!sctx->null_const_buf.buffer)
 			goto fail;
 		sctx->null_const_buf.buffer_size = sctx->null_const_buf.buffer->width0;
 
 		for (shader = 0; shader < SI_NUM_SHADERS; shader++) {
 			for (i = 0; i < SI_NUM_CONST_BUFFERS; i++) {
 				sctx->b.b.set_constant_buffer(&sctx->b.b, shader, i,
 							      &sctx->null_const_buf);
 			}
 		}
 
+		si_set_rw_buffer(sctx, SI_HS_CONST_DEFAULT_TESS_LEVELS,
+				 &sctx->null_const_buf);
+		si_set_rw_buffer(sctx, SI_VS_CONST_CLIP_PLANES,
+				 &sctx->null_const_buf);
+		si_set_rw_buffer(sctx, SI_PS_CONST_POLY_STIPPLE,
+				 &sctx->null_const_buf);
+		si_set_rw_buffer(sctx, SI_PS_CONST_SAMPLE_POSITIONS,
+				 &sctx->null_const_buf);
+
 		/* Clear the NULL constant buffer, because loads should return zeros. */
 		sctx->b.clear_buffer(&sctx->b.b, sctx->null_const_buf.buffer, 0,
 				     sctx->null_const_buf.buffer->width0, 0,
 				     R600_COHERENCY_SHADER);
 	}
 
 	uint64_t max_threads_per_block;
 	screen->get_compute_param(screen, PIPE_SHADER_IR_TGSI,
 				  PIPE_COMPUTE_CAP_MAX_THREADS_PER_BLOCK,
 				  &max_threads_per_block);
-- 
2.7.4