[Mesa-dev] [PATCH 1/2] i965: Disable unused transform feedback buffers.

[Iago Toral Quiroga]

If we are not recording any varying data to a particular transform feedback
buffer, disable it.
---
 src/mesa/drivers/dri/i965/gen7_sol_state.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/gen7_sol_state.c b/src/mesa/drivers/dri/i965/gen7_sol_state.c
index d2c3ae3..1aae659 100644
--- a/src/mesa/drivers/dri/i965/gen7_sol_state.c
+++ b/src/mesa/drivers/dri/i965/gen7_sol_state.c
@@ -220,6 +220,8 @@ upload_3dstate_streamout(struct brw_context *brw, bool active,
    /* BRW_NEW_TRANSFORM_FEEDBACK */
    struct gl_transform_feedback_object *xfb_obj =
       ctx->TransformFeedback.CurrentObject;
+   const struct gl_transform_feedback_info *linked_xfb_info =
+      &xfb_obj->shader_program->LinkedTransformFeedback;
    uint32_t dw1 = 0, dw2 = 0;
    int i;
 
@@ -250,9 +252,9 @@ upload_3dstate_streamout(struct brw_context *brw, bool active,
 	 dw1 |= SO_REORDER_TRAILING;
 
       for (i = 0; i < 4; i++) {
-	 if (xfb_obj->Buffers[i]) {
-	    dw1 |= SO_BUFFER_ENABLE(i);
-	 }
+         if (xfb_obj->Buffers[i] && linked_xfb_info->BufferStride[i] > 0) {
+            dw1 |= SO_BUFFER_ENABLE(i);
+         }
       }
 
       /* We always read the whole vertex.  This could be reduced at some
-- 
1.9.1