[Mesa-dev] [PATCH] gallium/util: handle patches in u_prims_for_vertices to fix a radeonsi crash

[Marek Olšák]

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

I guess the crash was because of divison by zero.

Cc: 11.0 11.1 <mesa-stable at lists.freedesktop.org>
---
 src/gallium/auxiliary/util/u_prim.h          | 17 +++++++++++++----
 src/gallium/drivers/radeonsi/si_state_draw.c |  3 ++-
 2 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/src/gallium/auxiliary/util/u_prim.h b/src/gallium/auxiliary/util/u_prim.h
index 3668015..4926af6 100644
--- a/src/gallium/auxiliary/util/u_prim.h
+++ b/src/gallium/auxiliary/util/u_prim.h
@@ -141,14 +141,23 @@ u_prim_vertex_count(unsigned prim)
  * For polygons, return the number of triangles.
  */
 static inline unsigned
-u_prims_for_vertices(unsigned prim, unsigned num)
+u_prims_for_vertices(unsigned prim, unsigned num, unsigned vertices_per_patch)
 {
-   const struct u_prim_vertex_count *info = u_prim_vertex_count(prim);
+   struct u_prim_vertex_count info;
 
-   if (num < info->min)
+   if (prim == PIPE_PRIM_PATCHES)
+      info.min = info.incr = vertices_per_patch;
+   else if (prim < PIPE_PRIM_MAX)
+      info = *u_prim_vertex_count(prim);
+   else {
+      assert(!"invalid prim type");
+      return 0;
+   }
+
+   if (num < info.min)
       return 0;
 
-   return 1 + ((num - info->min) / info->incr);
+   return 1 + ((num - info.min) / info.incr);
 }
 
 static inline boolean u_validate_pipe_prim( unsigned pipe_prim, unsigned nr )
diff --git a/src/gallium/drivers/radeonsi/si_state_draw.c b/src/gallium/drivers/radeonsi/si_state_draw.c
index ee84a1f..4ac9d0a 100644
--- a/src/gallium/drivers/radeonsi/si_state_draw.c
+++ b/src/gallium/drivers/radeonsi/si_state_draw.c
@@ -320,7 +320,8 @@ static unsigned si_get_ia_multi_vgt_param(struct si_context *sctx,
 	if (sctx->b.screen->info.max_se >= 2 && ia_switch_on_eoi &&
 	    (info->indirect ||
 	     (info->instance_count > 1 &&
-	      u_prims_for_vertices(info->mode, info->count) <= 1)))
+	      u_prims_for_vertices(info->mode, info->count,
+				   info->vertices_per_patch) <= 1)))
 		sctx->b.flags |= SI_CONTEXT_VGT_FLUSH;
 
 	return S_028AA8_SWITCH_ON_EOP(ia_switch_on_eop) |
-- 
2.1.4