drm/i915: Test request ordering between engines

A request on one engine with a dependency on a request on another engine
must wait for completion of the first request before starting.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170213171558.20942-15-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/selftests/i915_gem_request.c

@@ -521,11 +521,143 @@ out_unlock:
 	return err;
 }
 
+static int live_sequential_engines(void *arg)
+{
+	struct drm_i915_private *i915 = arg;
+	struct drm_i915_gem_request *request[I915_NUM_ENGINES] = {};
+	struct drm_i915_gem_request *prev = NULL;
+	struct intel_engine_cs *engine;
+	struct live_test t;
+	unsigned int id;
+	int err;
+
+	/* Check we can submit requests to all engines sequentially, such
+	 * that each successive request waits for the earlier ones. This
+	 * tests that we don't execute requests out of order, even though
+	 * they are running on independent engines.
+	 */
+
+	mutex_lock(&i915->drm.struct_mutex);
+
+	err = begin_live_test(&t, i915, __func__, "");
+	if (err)
+		goto out_unlock;
+
+	for_each_engine(engine, i915, id) {
+		struct i915_vma *batch;
+
+		batch = recursive_batch(i915);
+		if (IS_ERR(batch)) {
+			err = PTR_ERR(batch);
+			pr_err("%s: Unable to create batch for %s, err=%d\n",
+			       __func__, engine->name, err);
+			goto out_unlock;
+		}
+
+		request[id] = i915_gem_request_alloc(engine,
+						     i915->kernel_context);
+		if (IS_ERR(request[id])) {
+			err = PTR_ERR(request[id]);
+			pr_err("%s: Request allocation failed for %s with err=%d\n",
+			       __func__, engine->name, err);
+			goto out_request;
+		}
+
+		if (prev) {
+			err = i915_gem_request_await_dma_fence(request[id],
+							       &prev->fence);
+			if (err) {
+				i915_add_request(request[id]);
+				pr_err("%s: Request await failed for %s with err=%d\n",
+				       __func__, engine->name, err);
+				goto out_request;
+			}
+		}
+
+		err = engine->emit_flush(request[id], EMIT_INVALIDATE);
+		GEM_BUG_ON(err);
+
+		err = i915_switch_context(request[id]);
+		GEM_BUG_ON(err);
+
+		err = engine->emit_bb_start(request[id],
+					    batch->node.start,
+					    batch->node.size,
+					    0);
+		GEM_BUG_ON(err);
+		request[id]->batch = batch;
+
+		i915_vma_move_to_active(batch, request[id], 0);
+		i915_gem_object_set_active_reference(batch->obj);
+		i915_vma_get(batch);
+
+		i915_gem_request_get(request[id]);
+		i915_add_request(request[id]);
+
+		prev = request[id];
+	}
+
+	for_each_engine(engine, i915, id) {
+		long timeout;
+
+		if (i915_gem_request_completed(request[id])) {
+			pr_err("%s(%s): request completed too early!\n",
+			       __func__, engine->name);
+			err = -EINVAL;
+			goto out_request;
+		}
+
+		err = recursive_batch_resolve(request[id]->batch);
+		if (err) {
+			pr_err("%s: failed to resolve batch, err=%d\n",
+			       __func__, err);
+			goto out_request;
+		}
+
+		timeout = i915_wait_request(request[id],
+					    I915_WAIT_LOCKED,
+					    MAX_SCHEDULE_TIMEOUT);
+		if (timeout < 0) {
+			err = timeout;
+			pr_err("%s: error waiting for request on %s, err=%d\n",
+			       __func__, engine->name, err);
+			goto out_request;
+		}
+
+		GEM_BUG_ON(!i915_gem_request_completed(request[id]));
+	}
+
+	err = end_live_test(&t);
+
+out_request:
+	for_each_engine(engine, i915, id) {
+		u32 *cmd;
+
+		if (!request[id])
+			break;
+
+		cmd = i915_gem_object_pin_map(request[id]->batch->obj,
+					      I915_MAP_WC);
+		if (!IS_ERR(cmd)) {
+			*cmd = MI_BATCH_BUFFER_END;
+			wmb();
+			i915_gem_object_unpin_map(request[id]->batch->obj);
+		}
+
+		i915_vma_put(request[id]->batch);
+		i915_gem_request_put(request[id]);
+	}
+out_unlock:
+	mutex_unlock(&i915->drm.struct_mutex);
+	return err;
+}
+
 int i915_gem_request_live_selftests(struct drm_i915_private *i915)
 {
 	static const struct i915_subtest tests[] = {
 		SUBTEST(live_nop_request),
 		SUBTEST(live_all_engines),
+		SUBTEST(live_sequential_engines),
 	};
 	return i915_subtests(tests, i915);
 }