[Mesa-dev] [PATCH] radeonsi: avoid sending GS_EMIT in shaders without outputs

[Józef Kucia]

Fixes GPU hangs.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=107857
Signed-off-by: Józef Kucia <joseph.kucia at gmail.com>
---
 src/gallium/drivers/radeonsi/si_shader.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/src/gallium/drivers/radeonsi/si_shader.c b/src/gallium/drivers/radeonsi/si_shader.c
index 36f58e2ce52c..fedc616ebf61 100644
--- a/src/gallium/drivers/radeonsi/si_shader.c
+++ b/src/gallium/drivers/radeonsi/si_shader.c
@@ -4326,9 +4326,12 @@ static void si_llvm_emit_vertex(struct ac_shader_abi *abi,
 	gs_next_vertex = LLVMBuildAdd(ctx->ac.builder, gs_next_vertex, ctx->i32_1, "");
 	LLVMBuildStore(ctx->ac.builder, gs_next_vertex, ctx->gs_next_vertex[stream]);
 
-	/* Signal vertex emission */
-	ac_build_sendmsg(&ctx->ac, AC_SENDMSG_GS_OP_EMIT | AC_SENDMSG_GS | (stream << 8),
-			 si_get_gs_wave_id(ctx));
+	/* Signal vertex emission if vertex data was written. */
+	if (offset) {
+		ac_build_sendmsg(&ctx->ac, AC_SENDMSG_GS_OP_EMIT | AC_SENDMSG_GS | (stream << 8),
+				 si_get_gs_wave_id(ctx));
+	}
+
 	if (!use_kill)
 		lp_build_endif(&if_state);
 }
-- 
2.16.4