sna/gen6: stall before blending dirty pixels from the render cache

Another restriction on the render pipeline, it turns out, is that before
the blend unit can read back the dst pixels in a subsequent primitive,
we must stall the pipeline for the completion of that earlier primitive.

This is demonstrated by cacomposite.

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

1 files changed, 20 insertions, 10 deletions

diff --git a/src/sna/gen6_render.c b/src/sna/gen6_render.c
index 60b04465..371e999b 100644
--- a/src/sna/gen6_render.c
+++ b/src/sna/gen6_render.c
@@ -556,7 +556,7 @@ gen6_emit_invariant(struct sna *sna)
 	sna->render_state.gen6.needs_invariant = FALSE;
 }
 
-static void
+static bool
 gen6_emit_cc(struct sna *sna,
 	     int op, bool has_component_alpha, uint32_t dst_format)
 {
@@ -570,7 +570,7 @@ gen6_emit_cc(struct sna *sna,
 	     op, has_component_alpha, dst_format,
 	     blend, render->blend));
 	if (render->blend == blend)
-		return;
+		return op <= PictOpSrc;
 
 	if (op == PictOpClear) {
 		uint32_t src;
@@ -580,7 +580,7 @@ gen6_emit_cc(struct sna *sna,
 		 */
 		src = BLEND_OFFSET(GEN6_BLENDFACTOR_ONE, GEN6_BLENDFACTOR_ZERO);
 		if (render->blend == src)
-			return;
+			return true;
 	}
 
 	OUT_BATCH(GEN6_3DSTATE_CC_STATE_POINTERS | (4 - 2));
@@ -594,6 +594,7 @@ gen6_emit_cc(struct sna *sna,
 	}
 
 	render->blend = blend;
+	return op <= PictOpSrc;
 }
 
 static void
@@ -837,9 +838,10 @@ gen6_emit_state(struct sna *sna,
 		const struct sna_composite_op *op,
 		uint16_t wm_binding_table)
 {
-	bool need_stall;
+	bool need_stall = wm_binding_table & 1;
 
-	gen6_emit_cc(sna, op->op, op->has_component_alpha, op->dst.format);
+	if (gen6_emit_cc(sna, op->op, op->has_component_alpha, op->dst.format))
+		need_stall = false;
 	gen6_emit_sampler(sna,
 			  SAMPLER_OFFSET(op->src.filter,
 					 op->src.repeat,
@@ -851,7 +853,7 @@ gen6_emit_state(struct sna *sna,
 		     op->u.gen6.nr_surfaces,
 		     op->u.gen6.nr_inputs);
 	gen6_emit_vertex_elements(sna, op);
-	need_stall = gen6_emit_binding_table(sna, wm_binding_table);
+	need_stall |= gen6_emit_binding_table(sna, wm_binding_table & ~1);
 	if (gen6_emit_drawing_rectangle(sna, op))
 		need_stall = false;
 	if (kgem_bo_is_dirty(op->src.bo) || kgem_bo_is_dirty(op->mask.bo)) {
@@ -1641,8 +1643,10 @@ static void gen6_emit_composite_state(struct sna *sna,
 {
 	uint32_t *binding_table;
 	uint16_t offset;
+	bool dirty;
 
 	gen6_get_batch(sna);
+	dirty = kgem_bo_is_dirty(op->dst.bo);
 
 	binding_table = gen6_composite_get_binding_table(sna, &offset);
 
@@ -1674,7 +1678,7 @@ static void gen6_emit_composite_state(struct sna *sna,
 		offset = sna->render_state.gen6.surface_table;
 	}
 
-	gen6_emit_state(sna, op, offset);
+	gen6_emit_state(sna, op, offset | dirty);
 }
 
 static void
@@ -1849,9 +1853,11 @@ static void gen6_emit_video_state(struct sna *sna,
 	int src_pitch[6];
 	uint32_t *binding_table;
 	uint16_t offset;
+	bool dirty;
 	int n_src, n;
 
 	gen6_get_batch(sna);
+	dirty = kgem_bo_is_dirty(op->dst.bo);
 
 	src_surf_base[0] = 0;
 	src_surf_base[1] = 0;
@@ -1902,7 +1908,7 @@ static void gen6_emit_video_state(struct sna *sna,
 					       src_surf_format);
 	}
 
-	gen6_emit_state(sna, op, offset);
+	gen6_emit_state(sna, op, offset | dirty);
 }
 
 static Bool
@@ -2999,8 +3005,10 @@ gen6_emit_copy_state(struct sna *sna,
 {
 	uint32_t *binding_table;
 	uint16_t offset;
+	bool dirty;
 
 	gen6_get_batch(sna);
+	dirty = kgem_bo_is_dirty(op->dst.bo);
 
 	binding_table = gen6_composite_get_binding_table(sna, &offset);
 
@@ -3021,7 +3029,7 @@ gen6_emit_copy_state(struct sna *sna,
 		offset = sna->render_state.gen6.surface_table;
 	}
 
-	gen6_emit_state(sna, op, offset);
+	gen6_emit_state(sna, op, offset | dirty);
 }
 
 static inline bool untiled_tlb_miss(struct kgem_bo *bo)
@@ -3342,8 +3350,10 @@ gen6_emit_fill_state(struct sna *sna, const struct sna_composite_op *op)
 {
 	uint32_t *binding_table;
 	uint16_t offset;
+	bool dirty;
 
 	gen6_get_batch(sna);
+	dirty = kgem_bo_is_dirty(op->dst.bo);
 
 	binding_table = gen6_composite_get_binding_table(sna, &offset);
 
@@ -3365,7 +3375,7 @@ gen6_emit_fill_state(struct sna *sna, const struct sna_composite_op *op)
 		offset = sna->render_state.gen6.surface_table;
 	}
 
-	gen6_emit_state(sna, op, offset);
+	gen6_emit_state(sna, op, offset | dirty);
 }
 
 static inline bool prefer_blt_fill(struct sna *sna,