drm/i915/gt: Use the local engine wakeref when checking RING registers

Now that we can atomically acquire the engine wakeref, make use of it
when check whether the RING registers are idle.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190812091045.29587-7-chris@chris-wilson.co.uk

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

@@ -1008,16 +1008,12 @@ void intel_engine_get_instdone(struct intel_engine_cs *engine,
 
 static bool ring_is_idle(struct intel_engine_cs *engine)
 {
-	struct drm_i915_private *dev_priv = engine->i915;
-	intel_wakeref_t wakeref;
 	bool idle = true;
 
 	if (I915_SELFTEST_ONLY(!engine->mmio_base))
 		return true;
 
-	/* If the whole device is asleep, the engine must be idle */
-	wakeref = intel_runtime_pm_get_if_in_use(&dev_priv->runtime_pm);
-	if (!wakeref)
+	if (!intel_engine_pm_get_if_awake(engine))
 		return true;
 
 	/* First check that no commands are left in the ring */
@@ -1026,11 +1022,11 @@ static bool ring_is_idle(struct intel_engine_cs *engine)
 		idle = false;
 
 	/* No bit for gen2, so assume the CS parser is idle */
-	if (INTEL_GEN(dev_priv) > 2 &&
+	if (INTEL_GEN(engine->i915) > 2 &&
 	    !(ENGINE_READ(engine, RING_MI_MODE) & MODE_IDLE))
 		idle = false;
 
-	intel_runtime_pm_put(&dev_priv->runtime_pm, wakeref);
+	intel_engine_pm_put(engine);
 
 	return idle;
 }