drm/i915/guc: Keep the execbuf client allocated across reset

In order to avoid some complexity in trying to reconstruct the
workqueues across reset, remember them instead. The issue comes when we
have to handle a reset between request allocation and submission, the
request has reserved space in the wq, but is not in any list so we fail
to restore the reserved space. By keeping the execbuf client intact
across the reset, we also keep the reservations.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161129121024.22650-5-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_guc_submission.c

@@ -139,13 +139,6 @@ static int guc_update_doorbell_id(struct intel_guc *guc,
 	return guc_allocate_doorbell(guc, client);
 }
 
-static int guc_init_doorbell(struct intel_guc *guc,
-			      struct i915_guc_client *client,
-			      uint16_t db_id)
-{
-	return guc_update_doorbell_id(guc, client, db_id);
-}
-
 static void guc_disable_doorbell(struct intel_guc *guc,
 				 struct i915_guc_client *client)
 {
@@ -666,8 +659,7 @@ static void guc_init_doorbell_hw(struct intel_guc *guc)
 	uint16_t db_id;
 	int i, err;
 
-	/* Save client's original doorbell selection */
-	db_id = client->doorbell_id;
+	guc_disable_doorbell(guc, client);
 
 	for (i = 0; i < GUC_MAX_DOORBELLS; ++i) {
 		/* Skip if doorbell is OK */
@@ -680,7 +672,9 @@ static void guc_init_doorbell_hw(struct intel_guc *guc)
 					i, err);
 	}
 
-	/* Restore to original value */
+	db_id = select_doorbell_register(guc, client->priority);
+	WARN_ON(db_id == GUC_INVALID_DOORBELL_ID);
+
 	err = guc_update_doorbell_id(guc, client, db_id);
 	if (err)
 		DRM_WARN("Failed to restore doorbell to %d, err %d\n",
@@ -770,8 +764,13 @@ guc_client_alloc(struct drm_i915_private *dev_priv,
 
 	guc_proc_desc_init(guc, client);
 	guc_ctx_desc_init(guc, client);
-	if (guc_init_doorbell(guc, client, db_id))
-		goto err;
+
+	/* For runtime client allocation we need to enable the doorbell. Not
+	 * required yet for the static execbuf_client as this special kernel
+	 * client is enabled from i915_guc_submission_enable().
+	 *
+	 * guc_update_doorbell_id(guc, client, db_id);
+	 */
 
 	DRM_DEBUG_DRIVER("new priority %u client %p for engine(s) 0x%x: ctx_index %u\n",
 		priority, client, client->engines, client->ctx_index);
@@ -1371,6 +1370,9 @@ int i915_guc_submission_init(struct drm_i915_private *dev_priv)
 	struct intel_guc *guc = &dev_priv->guc;
 	struct i915_vma *vma;
 
+	if (!HAS_GUC_SCHED(dev_priv))
+		return 0;
+
 	/* Wipe bitmap & delete client in case of reinitialisation */
 	bitmap_clear(guc->doorbell_bitmap, 0, GUC_MAX_DOORBELLS);
 	i915_guc_submission_disable(dev_priv);
@@ -1390,42 +1392,58 @@ int i915_guc_submission_init(struct drm_i915_private *dev_priv)
 	guc_log_create(guc);
 	guc_addon_create(guc);
 
+	guc->execbuf_client = guc_client_alloc(dev_priv,
+					       INTEL_INFO(dev_priv)->ring_mask,
+					       GUC_CTX_PRIORITY_KMD_NORMAL,
+					       dev_priv->kernel_context);
+	if (!guc->execbuf_client) {
+		DRM_ERROR("Failed to create GuC client for execbuf!\n");
+		goto err;
+	}
+
 	return 0;
+
+err:
+	i915_guc_submission_fini(dev_priv);
+	return -ENOMEM;
+}
+
+static void guc_reset_wq(struct i915_guc_client *gc)
+{
+	struct guc_process_desc *desc = gc->vaddr + gc->proc_desc_offset;
+
+	desc->head = 0;
+	desc->tail = 0;
+
+	gc->wq_tail = 0;
 }
 
 int i915_guc_submission_enable(struct drm_i915_private *dev_priv)
 {
 	struct intel_guc *guc = &dev_priv->guc;
-	struct drm_i915_gem_request *request;
-	struct i915_guc_client *client;
+	struct i915_guc_client *client = guc->execbuf_client;
 	struct intel_engine_cs *engine;
 	enum intel_engine_id id;
 
-	/* client for execbuf submission */
-	client = guc_client_alloc(dev_priv,
-				  INTEL_INFO(dev_priv)->ring_mask,
-				  GUC_CTX_PRIORITY_KMD_NORMAL,
-				  dev_priv->kernel_context);
-	if (!client) {
-		DRM_ERROR("Failed to create normal GuC client!\n");
-		return -ENOMEM;
-	}
+	if (!client)
+		return -ENODEV;
 
-	guc->execbuf_client = client;
 	intel_guc_sample_forcewake(guc);
+
+	guc_reset_wq(client);
 	guc_init_doorbell_hw(guc);
 
 	/* Take over from manual control of ELSP (execlists) */
 	for_each_engine(engine, dev_priv, id) {
+		struct drm_i915_gem_request *rq;
+
 		engine->submit_request = i915_guc_submit;
 		engine->schedule = NULL;
 
 		/* Replay the current set of previously submitted requests */
-		list_for_each_entry(request,
-				    &engine->timeline->requests, link) {
+		list_for_each_entry(rq, &engine->timeline->requests, link) {
 			client->wq_rsvd += sizeof(struct guc_wq_item);
-			if (i915_sw_fence_done(&request->submit))
-				i915_guc_submit(request);
+			i915_guc_submit(rq);
 		}
 	}
 
@@ -1441,14 +1459,18 @@ void i915_guc_submission_disable(struct drm_i915_private *dev_priv)
 
 	/* Revert back to manual ELSP submission */
 	intel_execlists_enable_submission(dev_priv);
-
-	guc_client_free(dev_priv, guc->execbuf_client);
-	guc->execbuf_client = NULL;
 }
 
 void i915_guc_submission_fini(struct drm_i915_private *dev_priv)
 {
 	struct intel_guc *guc = &dev_priv->guc;
+	struct i915_guc_client *client;
+
+	client = fetch_and_zero(&guc->execbuf_client);
+	if (!client)
+		return;
+
+	guc_client_free(dev_priv, client);
 
 	i915_vma_unpin_and_release(&guc->ads_vma);
 	i915_vma_unpin_and_release(&guc->log.vma);