Mesa (master): radeonsi: fix VM faults due NULL internal const buffers on CIK

[Marek Olšák]

Module: Mesa
Branch: master
Commit: 2c13abb49137d0f81b530b3c67f1ed79c58c796e
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=2c13abb49137d0f81b530b3c67f1ed79c58c796e

Author: Marek Olšák <marek.olsak at amd.com>
Date:   Thu Aug 18 15:25:51 2016 +0200

radeonsi: fix VM faults due NULL internal const buffers on CIK

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 131d3a2..67c3a26 100644
--- a/src/gallium/drivers/radeonsi/si_pipe.c
+++ b/src/gallium/drivers/radeonsi/si_pipe.c
@@ -251,8 +251,8 @@ static struct pipe_context *si_create_context(struct pipe_screen *screen,
 	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);
@@ -267,6 +267,15 @@ static struct pipe_context *si_create_context(struct pipe_screen *screen,
 			}
 		}
 
+		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,