[Mesa-dev] [PATCH 2/4] radeonsi: skip draws with instance_count == 0

[Marek Olšák]

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

loosely ported from Vulkan
---
 src/gallium/drivers/radeonsi/si_state_draw.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/src/gallium/drivers/radeonsi/si_state_draw.c b/src/gallium/drivers/radeonsi/si_state_draw.c
index 0a91291..9469bb4 100644
--- a/src/gallium/drivers/radeonsi/si_state_draw.c
+++ b/src/gallium/drivers/radeonsi/si_state_draw.c
@@ -875,23 +875,33 @@ void si_ce_post_draw_synchronization(struct si_context *sctx)
 	}
 }
 
 void si_draw_vbo(struct pipe_context *ctx, const struct pipe_draw_info *info)
 {
 	struct si_context *sctx = (struct si_context *)ctx;
 	struct si_state_rasterizer *rs = sctx->queued.named.rasterizer;
 	struct pipe_index_buffer ib = {};
 	unsigned mask, dirty_fb_counter, dirty_tex_counter, rast_prim;
 
-	if (!info->count && !info->indirect &&
-	    (info->indexed || !info->count_from_stream_output))
-		return;
+	if (likely(!info->indirect)) {
+		/* SI-CI treat instance_count==0 as instance_count==1. There is
+		 * no workaround for indirect draws, but we can at least skip
+		 * direct draws.
+		 */
+		if (unlikely(!info->instance_count))
+			return;
+
+		/* Handle count == 0. */
+		if (unlikely(!info->count &&
+			     (info->indexed || !info->count_from_stream_output)))
+			return;
+	}
 
 	if (!sctx->vs_shader.cso) {
 		assert(0);
 		return;
 	}
 	if (!sctx->ps_shader.cso && (!rs || !rs->rasterizer_discard)) {
 		assert(0);
 		return;
 	}
 	if (!!sctx->tes_shader.cso != (info->mode == PIPE_PRIM_PATCHES)) {
-- 
2.7.4