sna/gen3+: Flush vertex threads before touching global state

We need to be careful not just when finishing the current vbo to
synchronize with the sharing threads, but also before we emit the batch
state that no other thread will try and do the same.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 11 insertions, 12 deletions

diff --git a/src/sna/gen6_render.c b/src/sna/gen6_render.c
index a9d81114..ec642504 100644
--- a/src/sna/gen6_render.c
+++ b/src/sna/gen6_render.c
@@ -1125,6 +1125,9 @@ static bool gen6_rectangle_begin(struct sna *sna,
 	int id = 1 << GEN6_VERTEX(op->u.gen6.flags);
 	int ndwords;
 
+	if (sna_vertex_wait__locked(&sna->render) && sna->render.vertex_offset)
+		return true;
+
 	ndwords = op->need_magic_ca_pass ? 60 : 6;
 	if ((sna->render.vb_id & id) == 0)
 		ndwords += 5;
@@ -1141,6 +1144,13 @@ static bool gen6_rectangle_begin(struct sna *sna,
 static int gen6_get_rectangles__flush(struct sna *sna,
 				      const struct sna_composite_op *op)
 {
+	/* Preventing discarding new vbo after lock contention */
+	if (sna_vertex_wait__locked(&sna->render)) {
+		int rem = vertex_space(sna);
+		if (rem > op->floats_per_rect)
+			return rem;
+	}
+
 	if (!kgem_check_batch(&sna->kgem, op->need_magic_ca_pass ? 65 : 5))
 		return 0;
 	if (!kgem_check_reloc_and_exec(&sna->kgem, 2))
@@ -1157,17 +1167,6 @@ static int gen6_get_rectangles__flush(struct sna *sna,
 		}
 	}
 
-	/* Preventing discarding new vbo after lock contention */
-	if (sna->render.active) {
-		int rem;
-
-		sna_vertex_wait__locked(&sna->render);
-
-		rem = vertex_space(sna);
-		if (rem > op->floats_per_rect)
-			return rem;
-	}
-
 	return gen4_vertex_finish(sna);
 }
 
@@ -1180,7 +1179,7 @@ inline static int gen6_get_rectangles(struct sna *sna,
 
 start:
 	rem = vertex_space(sna);
-	if (rem < op->floats_per_rect) {
+	if (unlikely(rem < op->floats_per_rect)) {
 		DBG(("flushing vbo for %s: %d < %d\n",
 		     __FUNCTION__, rem, op->floats_per_rect));
 		rem = gen6_get_rectangles__flush(sna, op);