[Mesa-dev] [PATCH 3/4] i965/gen6: Limit the workaround flush to once per primitive.

[Eric Anholt]

We're about to call this function in a bunch of state emits, so let's
not spam the hardware with flushes too hard.
---
 src/mesa/drivers/dri/i965/brw_draw.c           |    2 ++
 src/mesa/drivers/dri/i965/brw_vtbl.c           |    5 +++++
 src/mesa/drivers/dri/intel/intel_batchbuffer.c |    5 +++++
 src/mesa/drivers/dri/intel/intel_context.h     |    2 ++
 4 files changed, 14 insertions(+), 0 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_draw.c b/src/mesa/drivers/dri/i965/brw_draw.c
index 6144f0a..350fc51 100644
--- a/src/mesa/drivers/dri/i965/brw_draw.c
+++ b/src/mesa/drivers/dri/i965/brw_draw.c
@@ -177,6 +177,8 @@ static void brw_emit_prim(struct brw_context *brw,
    OUT_BATCH(base_vertex_location);
    ADVANCE_BATCH();
 
+   intel->batch.need_workaround_flush = true;
+
    if (intel->always_flush_cache) {
       intel_batchbuffer_emit_mi_flush(intel);
    }
diff --git a/src/mesa/drivers/dri/i965/brw_vtbl.c b/src/mesa/drivers/dri/i965/brw_vtbl.c
index 236c4d2..ed4c9c6 100644
--- a/src/mesa/drivers/dri/i965/brw_vtbl.c
+++ b/src/mesa/drivers/dri/i965/brw_vtbl.c
@@ -124,6 +124,11 @@ static void brw_new_batch( struct intel_context *intel )
     */
    brw->state.dirty.brw |= BRW_NEW_CONTEXT | BRW_NEW_BATCH;
 
+   /* Assume that the last command before the start of our batch was a
+    * primitive, for safety.
+    */
+   intel->batch.need_workaround_flush = true;
+
    brw->vb.nr_current_buffers = 0;
 }
 
diff --git a/src/mesa/drivers/dri/intel/intel_batchbuffer.c b/src/mesa/drivers/dri/intel/intel_batchbuffer.c
index 9e8f8b5..77563ae 100644
--- a/src/mesa/drivers/dri/intel/intel_batchbuffer.c
+++ b/src/mesa/drivers/dri/intel/intel_batchbuffer.c
@@ -296,6 +296,9 @@ emit:
 static void
 intel_emit_post_sync_nonzero_flush(struct intel_context *intel)
 {
+   if (!intel->batch.need_workaround_flush)
+      return;
+
    BEGIN_BATCH(4);
    OUT_BATCH(_3DSTATE_PIPE_CONTROL);
    OUT_BATCH(PIPE_CONTROL_WRITE_IMMEDIATE);
@@ -303,6 +306,8 @@ intel_emit_post_sync_nonzero_flush(struct intel_context *intel)
 	     I915_GEM_DOMAIN_GTT, I915_GEM_DOMAIN_GTT, 0);
    OUT_BATCH(0); /* write data */
    ADVANCE_BATCH();
+
+   intel->batch.need_workaround_flush = false;
 }
 
 /* Emit a pipelined flush to either flush render and texture cache for
diff --git a/src/mesa/drivers/dri/intel/intel_context.h b/src/mesa/drivers/dri/intel/intel_context.h
index 751af45..148fb0c 100644
--- a/src/mesa/drivers/dri/intel/intel_context.h
+++ b/src/mesa/drivers/dri/intel/intel_context.h
@@ -183,6 +183,8 @@ struct intel_context
       drm_intel_bo *last_bo;
       /** BO for post-sync nonzero writes for gen6 workaround. */
       drm_intel_bo *workaround_bo;
+      bool need_workaround_flush;
+
       struct cached_batch_item *cached_items;
 
       uint16_t emit, total;
-- 
1.7.5.3