[PATCH 5/5] drm/i915/gt: Replace ring probe for engine_is_idle with i915_sched query

[Chris Wilson]

Now that we have a means to query whether the backend has an active
request, replace the ring_is_idle() check.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/gt/intel_engine_cs.c | 41 ++++++-----------------
 1 file changed, 11 insertions(+), 30 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_engine_cs.c b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
index 28d2a121f2c0..577ebd4a324f 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
@@ -1175,31 +1175,6 @@ void intel_engine_get_instdone(const struct intel_engine_cs *engine,
 	}
 }
 
-static bool ring_is_idle(struct intel_engine_cs *engine)
-{
-	bool idle = true;
-
-	if (I915_SELFTEST_ONLY(!engine->mmio_base))
-		return true;
-
-	if (!intel_engine_pm_get_if_awake(engine))
-		return true;
-
-	/* First check that no commands are left in the ring */
-	if ((ENGINE_READ(engine, RING_HEAD) & HEAD_ADDR) !=
-	    (ENGINE_READ(engine, RING_TAIL) & TAIL_ADDR))
-		idle = false;
-
-	/* No bit for gen2, so assume the CS parser is idle */
-	if (INTEL_GEN(engine->i915) > 2 &&
-	    !(ENGINE_READ(engine, RING_MI_MODE) & MODE_IDLE))
-		idle = false;
-
-	intel_engine_pm_put(engine);
-
-	return idle;
-}
-
 /**
  * intel_engine_is_idle() - Report if the engine has finished process all work
  * @engine: the intel_engine_cs
@@ -1210,14 +1185,12 @@ static bool ring_is_idle(struct intel_engine_cs *engine)
 bool intel_engine_is_idle(struct intel_engine_cs *engine)
 {
 	struct i915_sched *se = intel_engine_get_scheduler(engine);
+	struct i915_request *rq = NULL;
 
 	/* More white lies, if wedged, hw state is inconsistent */
 	if (intel_gt_is_wedged(engine->gt))
 		return true;
 
-	if (!intel_engine_pm_is_awake(engine))
-		return true;
-
 	/* Waiting to drain ELSP? */
 	synchronize_hardirq(to_pci_dev(engine->i915->drm.dev)->irq);
 	i915_sched_flush(se);
@@ -1226,8 +1199,16 @@ bool intel_engine_is_idle(struct intel_engine_cs *engine)
 	if (!i915_sched_is_idle(se))
 		return false;
 
-	/* Ring stopped? */
-	return ring_is_idle(engine);
+	/* Execution complete? */
+	if (intel_engine_pm_get_if_awake(engine)) {
+		spin_lock_irq(&se->lock);
+		rq = i915_sched_get_active_request(se);
+		spin_unlock_irq(&se->lock);
+
+		intel_engine_pm_put(engine);
+	}
+
+	return !rq;
 }
 
 bool intel_engines_are_idle(struct intel_gt *gt)
-- 
2.20.1