drm/i915/selftest: Fix hangcheck self test for GuC submission

When GuC submission is enabled, the GuC controls engine resets. Rather
than explicitly triggering a reset, the driver must submit a hanging
context to GuC and wait for the reset to occur.

Conversely, one of the tests specifically sends hanging batches to the
engines but wants them to sit around until a manual reset of the full
GT (including GuC itself). That means disabling GuC based engine
resets to prevent those from killing the hanging batch too soon. So,
add support to the scheduling policy helper for disabling resets as
well as making them quicker!

In GuC submission mode, the 'is engine idle' test basically turns into
'is engine PM wakelock held'. Independently, there is a heartbeat
disable helper function that the tests use. For unexplained reasons,
this acquires the engine wakelock before disabling the heartbeat and
only releases it when re-enabling the heartbeat. As one of the tests
tries to do a wait for idle in the middle of a heartbeat disabled
section, it is therefore guaranteed to always fail. Added a 'no_pm'
variant of the heartbeat helper that allows the engine to be asleep
while also having heartbeats disabled.

Signed-off-by: John Harrison <[email protected]>
Signed-off-by: Matthew Brost <[email protected]>
Reviewed-by: Matthew Brost <[email protected]>
Cc: Daniele Ceraolo Spurio <[email protected]>
Cc: Matthew Brost <[email protected]>
Signed-off-by: John Harrison <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]

Author: johnharr-intel

drivers/gpu/drm/i915/gt/selftest_engine_heartbeat.c

@@ -405,3 +405,25 @@ void st_engine_heartbeat_enable(struct intel_engine_cs *engine)
 	engine->props.heartbeat_interval_ms =
 		engine->defaults.heartbeat_interval_ms;
 }
+
+void st_engine_heartbeat_disable_no_pm(struct intel_engine_cs *engine)
+{
+	engine->props.heartbeat_interval_ms = 0;
+
+	/*
+	 * Park the heartbeat but without holding the PM lock as that
+	 * makes the engines appear not-idle. Note that if/when unpark
+	 * is called due to the PM lock being acquired later the
+	 * heartbeat still won't be enabled because of the above = 0.
+	 */
+	if (intel_engine_pm_get_if_awake(engine)) {
+		intel_engine_park_heartbeat(engine);
+		intel_engine_pm_put(engine);
+	}
+}
+
+void st_engine_heartbeat_enable_no_pm(struct intel_engine_cs *engine)
+{
+	engine->props.heartbeat_interval_ms =
+		engine->defaults.heartbeat_interval_ms;
+}

drivers/gpu/drm/i915/gt/selftest_engine_heartbeat.h

@@ -9,6 +9,8 @@
 struct intel_engine_cs;
 
 void st_engine_heartbeat_disable(struct intel_engine_cs *engine);
+void st_engine_heartbeat_disable_no_pm(struct intel_engine_cs *engine);
 void st_engine_heartbeat_enable(struct intel_engine_cs *engine);
+void st_engine_heartbeat_enable_no_pm(struct intel_engine_cs *engine);
 
 #endif /* SELFTEST_ENGINE_HEARTBEAT_H */