drm/i915: put context upon switching

In order to be notified of when the context and all of its associated objects is idle (for if the context maps to a ppgtt) we need a callback from the retire handler. We can arrange this by using the kref_get/put of the context for request tracking and by inserting a request to demarque the switch away from the old context. [Ben: fixed minor error to patch compile, AND s/last_context/from/] Signed-off-by: Ben Widawsky <ben@bwidawsk.net> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drm/i915: put context upon switching
In order to be notified of when the context and all of its associated objects is idle (for if the context maps to a ppgtt) we need a callback from the retire handler. We can arrange this by using the kref_get/put of the context for request tracking and by inserting a request to demarque the switch away from the old context. [Ben: fixed minor error to patch compile, AND s/last_context/from/] Signed-off-by: Ben Widawsky <ben@bwidawsk.net> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Chris Wilson · Daniel Vetter
1 parent 21a8e6a485
Showing 2 changed files with 25 additions and 14 deletions Side-by-side Diff
drivers/gpu/drm/i915/i915_gem_context.c
drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -361,13 +361,13 @@
 static int do_switch(struct i915_hw_context *to)
 {
 	struct intel_ring_buffer *ring = to->ring;
-	struct drm_i915_gem_object *from_obj = ring->last_context_obj;
+	struct i915_hw_context *from = ring->last_context;
 	u32 hw_flags = 0;
 	int ret;
  
-	BUG_ON(from_obj != NULL && from_obj->pin_count == 0);
+	BUG_ON(from != NULL && from->obj != NULL && from->obj->pin_count == 0);
  
-	if (from_obj == to->obj)
+	if (from == to)
 		return 0;
  
 	ret = i915_gem_object_pin(to->obj, CONTEXT_ALIGN, false, false);
@@ -390,7 +390,7 @@
  
 	if (!to->is_initialized || is_default_context(to))
 		hw_flags |= MI_RESTORE_INHIBIT;
-	else if (WARN_ON_ONCE(from_obj == to->obj)) /* not yet expected */
+	else if (WARN_ON_ONCE(from == to)) /* not yet expected */
 		hw_flags |= MI_FORCE_RESTORE;
  
 	ret = mi_set_context(ring, to, hw_flags);
@@ -405,9 +405,9 @@
 	 * is a bit suboptimal because the retiring can occur simply after the
 	 * MI_SET_CONTEXT instead of when the next seqno has completed.
 	 */
-	if (from_obj != NULL) {
-		from_obj->base.read_domains = I915_GEM_DOMAIN_INSTRUCTION;
-		i915_gem_object_move_to_active(from_obj, ring);
+	if (from != NULL) {
+		from->obj->base.read_domains = I915_GEM_DOMAIN_INSTRUCTION;
+		i915_gem_object_move_to_active(from->obj, ring);
 		/* As long as MI_SET_CONTEXT is serializing, ie. it flushes the
 		 * whole damn pipeline, we don't need to explicitly mark the
 		 * object dirty. The only exception is that the context must be
  
  
@@ -415,15 +415,26 @@
 		 * able to defer doing this until we know the object would be
 		 * swapped, but there is no way to do that yet.
 		 */
-		from_obj->dirty = 1;
-		BUG_ON(from_obj->ring != ring);
-		i915_gem_object_unpin(from_obj);
+		from->obj->dirty = 1;
+		BUG_ON(from->obj->ring != ring);
  
-		drm_gem_object_unreference(&from_obj->base);
+		ret = i915_add_request(ring, NULL, NULL);
+		if (ret) {
+			/* Too late, we've already scheduled a context switch.
+			 * Try to undo the change so that the hw state is
+			 * consistent with out tracking. In case of emergency,
+			 * scream.
+			 */
+			WARN_ON(mi_set_context(ring, from, MI_RESTORE_INHIBIT));
+			return ret;
+		}
+
+		i915_gem_object_unpin(from->obj);
+		i915_gem_context_unreference(from);
 	}
  
-	drm_gem_object_reference(&to->obj->base);
-	ring->last_context_obj = to->obj;
+	i915_gem_context_reference(to);
+	ring->last_context = to;
 	to->is_initialized = true;
  
 	return 0;
@@ -135,7 +135,7 @@
 	 */
 	bool itlb_before_ctx_switch;
 	struct i915_hw_context *default_context;
-	struct drm_i915_gem_object *last_context_obj;
+	struct i915_hw_context *last_context;
  
 	void *private;
 };
...	...	@@ -361,13 +361,13 @@
361	361	static int do_switch(struct i915_hw_context *to)
362	362	{
363	363	struct intel_ring_buffer *ring = to->ring;
364		- struct drm_i915_gem_object *from_obj = ring->last_context_obj;
	364	+ struct i915_hw_context *from = ring->last_context;
365	365	u32 hw_flags = 0;
366	366	int ret;
367	367
368		- BUG_ON(from_obj != NULL && from_obj->pin_count == 0);
	368	+ BUG_ON(from != NULL && from->obj != NULL && from->obj->pin_count == 0);
369	369
370		- if (from_obj == to->obj)
	370	+ if (from == to)
371	371	return 0;
372	372
373	373	ret = i915_gem_object_pin(to->obj, CONTEXT_ALIGN, false, false);
...	...	@@ -390,7 +390,7 @@
390	390
391	391	if (!to->is_initialized \|\| is_default_context(to))
392	392	hw_flags \|= MI_RESTORE_INHIBIT;
393		- else if (WARN_ON_ONCE(from_obj == to->obj)) /* not yet expected */
	393	+ else if (WARN_ON_ONCE(from == to)) /* not yet expected */
394	394	hw_flags \|= MI_FORCE_RESTORE;
395	395
396	396	ret = mi_set_context(ring, to, hw_flags);
...	...	@@ -405,9 +405,9 @@
405	405	* is a bit suboptimal because the retiring can occur simply after the
406	406	* MI_SET_CONTEXT instead of when the next seqno has completed.
407	407	*/
408		- if (from_obj != NULL) {
409		- from_obj->base.read_domains = I915_GEM_DOMAIN_INSTRUCTION;
410		- i915_gem_object_move_to_active(from_obj, ring);
	408	+ if (from != NULL) {
	409	+ from->obj->base.read_domains = I915_GEM_DOMAIN_INSTRUCTION;
	410	+ i915_gem_object_move_to_active(from->obj, ring);
411	411	/* As long as MI_SET_CONTEXT is serializing, ie. it flushes the
412	412	* whole damn pipeline, we don't need to explicitly mark the
413	413	* object dirty. The only exception is that the context must be
414	414
415	415
...	...	@@ -415,15 +415,26 @@
415	415	* able to defer doing this until we know the object would be
416	416	* swapped, but there is no way to do that yet.
417	417	*/
418		- from_obj->dirty = 1;
419		- BUG_ON(from_obj->ring != ring);
420		- i915_gem_object_unpin(from_obj);
	418	+ from->obj->dirty = 1;
	419	+ BUG_ON(from->obj->ring != ring);
421	420
422		- drm_gem_object_unreference(&from_obj->base);
	421	+ ret = i915_add_request(ring, NULL, NULL);
	422	+ if (ret) {
	423	+ /* Too late, we've already scheduled a context switch.
	424	+ * Try to undo the change so that the hw state is
	425	+ * consistent with out tracking. In case of emergency,
	426	+ * scream.
	427	+ */
	428	+ WARN_ON(mi_set_context(ring, from, MI_RESTORE_INHIBIT));
	429	+ return ret;
	430	+ }
	431	+
	432	+ i915_gem_object_unpin(from->obj);
	433	+ i915_gem_context_unreference(from);
423	434	}
424	435
425		- drm_gem_object_reference(&to->obj->base);
426		- ring->last_context_obj = to->obj;
	436	+ i915_gem_context_reference(to);
	437	+ ring->last_context = to;
427	438	to->is_initialized = true;
428	439
429	440	return 0;
...	...	@@ -135,7 +135,7 @@
135	135	*/
136	136	bool itlb_before_ctx_switch;
137	137	struct i915_hw_context *default_context;
138		- struct drm_i915_gem_object *last_context_obj;
	138	+ struct i915_hw_context *last_context;
139	139
140	140	void *private;
141	141	};