[PATCH 09/20] drm/i915: Stop mapping the scratch page into CPU space

Chris Wilson chris at chris-wilson.co.uk
Fri Jul 1 10:27:28 UTC 2016


After the elimination of using the scratch page for Ironlake's
breadcrumb, we no longer need to kmap the object. We therefore can move
it into the high unmappable space and do not need to force the object to
be coherent (i.e. snooped on !llc platforms).

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
---
 drivers/gpu/drm/i915/intel_ringbuffer.c | 40 +++++++++------------------------
 drivers/gpu/drm/i915/intel_ringbuffer.h |  1 -
 2 files changed, 11 insertions(+), 30 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 0c0f8c4ef547..304d1222b321 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -648,58 +648,40 @@ out:
 	return ret;
 }
 
-void
-intel_fini_pipe_control(struct intel_engine_cs *engine)
+void intel_fini_pipe_control(struct intel_engine_cs *engine)
 {
 	if (engine->scratch.obj == NULL)
 		return;
 
-	if (INTEL_GEN(engine->i915) >= 5) {
-		kunmap(sg_page(engine->scratch.obj->pages->sgl));
-		i915_gem_object_ggtt_unpin(engine->scratch.obj);
-	}
-
+	i915_gem_object_ggtt_unpin(engine->scratch.obj);
 	drm_gem_object_unreference(&engine->scratch.obj->base);
 	engine->scratch.obj = NULL;
 }
 
-int
-intel_init_pipe_control(struct intel_engine_cs *engine)
+int intel_init_pipe_control(struct intel_engine_cs *engine)
 {
+	struct drm_i915_gem_object *obj;
 	int ret;
 
 	WARN_ON(engine->scratch.obj);
 
-	engine->scratch.obj = i915_gem_object_create(engine->i915->dev, 4096);
-	if (IS_ERR(engine->scratch.obj)) {
-		DRM_ERROR("Failed to allocate seqno page\n");
-		ret = PTR_ERR(engine->scratch.obj);
-		engine->scratch.obj = NULL;
+	obj = i915_gem_object_create(engine->i915->dev, 4096);
+	if (IS_ERR(obj)) {
+		DRM_ERROR("Failed to allocate scratch page\n");
+		ret = PTR_ERR(obj);
 		goto err;
 	}
 
-	ret = i915_gem_object_set_cache_level(engine->scratch.obj,
-					      I915_CACHE_LLC);
+	ret = i915_gem_obj_ggtt_pin(obj, 4096, PIN_HIGH);
 	if (ret)
 		goto err_unref;
 
-	ret = i915_gem_obj_ggtt_pin(engine->scratch.obj, 4096, 0);
-	if (ret)
-		goto err_unref;
-
-	engine->scratch.gtt_offset = i915_gem_obj_ggtt_offset(engine->scratch.obj);
-	engine->scratch.cpu_page = kmap(sg_page(engine->scratch.obj->pages->sgl));
-	if (engine->scratch.cpu_page == NULL) {
-		ret = -ENOMEM;
-		goto err_unpin;
-	}
-
+	engine->scratch.obj = obj;
+	engine->scratch.gtt_offset = i915_gem_obj_ggtt_offset(obj);
 	DRM_DEBUG_DRIVER("%s pipe control offset: 0x%08x\n",
 			 engine->name, engine->scratch.gtt_offset);
 	return 0;
 
-err_unpin:
-	i915_gem_object_ggtt_unpin(engine->scratch.obj);
 err_unref:
 	drm_gem_object_unreference(&engine->scratch.obj->base);
 err:
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index 7a0f2fe2d41a..00bf86f92e1c 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -326,7 +326,6 @@ struct intel_engine_cs {
 	struct {
 		struct drm_i915_gem_object *obj;
 		u32 gtt_offset;
-		volatile u32 *cpu_page;
 	} scratch;
 
 	bool needs_cmd_parser;
-- 
2.8.1



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