1 files changed, 83 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/gt/selftest_engine_pm.c b/drivers/gpu/drm/i915/gt/selftest_engine_pm.c
new file mode 100644
index 000000000000..3a1419376912
--- /dev/null
+++ b/drivers/gpu/drm/i915/gt/selftest_engine_pm.c
@@ -0,0 +1,83 @@
+/*
+ * SPDX-License-Identifier: GPL-2.0
+ *
+ * Copyright © 2018 Intel Corporation
+ */
+
+#include "i915_selftest.h"
+#include "selftest_engine.h"
+#include "selftests/igt_atomic.h"
+
+static int live_engine_pm(void *arg)
+{
+	struct intel_gt *gt = arg;
+	struct intel_engine_cs *engine;
+	enum intel_engine_id id;
+
+	/*
+	 * Check we can call intel_engine_pm_put from any context. No
+	 * failures are reported directly, but if we mess up lockdep should
+	 * tell us.
+	 */
+	if (intel_gt_pm_wait_for_idle(gt)) {
+		pr_err("Unable to flush GT pm before test\n");
+		return -EBUSY;
+	}
+
+	GEM_BUG_ON(intel_gt_pm_is_awake(gt));
+	for_each_engine(engine, gt->i915, id) {
+		const typeof(*igt_atomic_phases) *p;
+
+		for (p = igt_atomic_phases; p->name; p++) {
+			/*
+			 * Acquisition is always synchronous, except if we
+			 * know that the engine is already awake, in which
+			 * case we should use intel_engine_pm_get_if_awake()
+			 * to atomically grab the wakeref.
+			 *
+			 * In practice,
+			 *    intel_engine_pm_get();
+			 *    intel_engine_pm_put();
+			 * occurs in one thread, while simultaneously
+			 *    intel_engine_pm_get_if_awake();
+			 *    intel_engine_pm_put();
+			 * occurs from atomic context in another.
+			 */
+			GEM_BUG_ON(intel_engine_pm_is_awake(engine));
+			intel_engine_pm_get(engine);
+
+			p->critical_section_begin();
+			if (!intel_engine_pm_get_if_awake(engine))
+				pr_err("intel_engine_pm_get_if_awake(%s) failed under %s\n",
+				       engine->name, p->name);
+			else
+				intel_engine_pm_put(engine);
+			intel_engine_pm_put(engine);
+			p->critical_section_end();
+
+			/* engine wakeref is sync (instant) */
+			if (intel_engine_pm_is_awake(engine)) {
+				pr_err("%s is still awake after flushing pm\n",
+				       engine->name);
+				return -EINVAL;
+			}
+
+			/* gt wakeref is async (deferred to workqueue) */
+			if (intel_gt_pm_wait_for_idle(gt)) {
+				pr_err("GT failed to idle\n");
+				return -EINVAL;
+			}
+		}
+	}
+
+	return 0;
+}
+
+int live_engine_pm_selftests(struct intel_gt *gt)
+{
+	static const struct i915_subtest tests[] = {
+		SUBTEST(live_engine_pm),
+	};
+
+	return intel_gt_live_subtests(tests, gt);
+}