drm/i915: Mark elsps submitted when they are pushed to hw

Now when we have requests this deep on call chain, we can mark
the elsp being submitted when it actually is. Remove temp variable
and readjust commenting to more closely fit to the code.

v2: Avoid tmp variable and reduce number of writes (Chris)

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NMika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_lrc.c

@@ -300,31 +300,29 @@ static void execlists_elsp_write(struct drm_i915_gem_request *rq0,
 	struct intel_engine_cs *ring = rq0->ring;
 	struct drm_device *dev = ring->dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
-	uint64_t temp = 0;
-	uint32_t desc[4];
+	uint64_t desc[2];
 
-	/* XXX: You must always write both descriptors in the order below. */
-	if (rq1)
-		temp = execlists_ctx_descriptor(rq1);
-	else
-		temp = 0;
-	desc[1] = (u32)(temp >> 32);
-	desc[0] = (u32)temp;
+	if (rq1) {
+		desc[1] = execlists_ctx_descriptor(rq1);
+		rq1->elsp_submitted++;
+	} else {
+		desc[1] = 0;
+	}
 
-	temp = execlists_ctx_descriptor(rq0);
-	desc[3] = (u32)(temp >> 32);
-	desc[2] = (u32)temp;
+	desc[0] = execlists_ctx_descriptor(rq0);
+	rq0->elsp_submitted++;
 
+	/* You must always write both descriptors in the order below. */
 	spin_lock(&dev_priv->uncore.lock);
 	intel_uncore_forcewake_get__locked(dev_priv, FORCEWAKE_ALL);
-	I915_WRITE_FW(RING_ELSP(ring), desc[1]);
-	I915_WRITE_FW(RING_ELSP(ring), desc[0]);
-	I915_WRITE_FW(RING_ELSP(ring), desc[3]);
+	I915_WRITE_FW(RING_ELSP(ring), upper_32_bits(desc[1]));
+	I915_WRITE_FW(RING_ELSP(ring), lower_32_bits(desc[1]));
 
+	I915_WRITE_FW(RING_ELSP(ring), upper_32_bits(desc[0]));
 	/* The context is automatically loaded after the following */
-	I915_WRITE_FW(RING_ELSP(ring), desc[2]);
+	I915_WRITE_FW(RING_ELSP(ring), lower_32_bits(desc[0]));
 
-	/* ELSP is a wo register, so use another nearby reg for posting instead */
+	/* ELSP is a wo register, use another nearby reg for posting */
 	POSTING_READ_FW(RING_EXECLIST_STATUS(ring));
 	intel_uncore_forcewake_put__locked(dev_priv, FORCEWAKE_ALL);
 	spin_unlock(&dev_priv->uncore.lock);
@@ -433,10 +431,6 @@ static void execlists_context_unqueue(struct intel_engine_cs *ring)
 	WARN_ON(req1 && req1->elsp_submitted);
 
 	execlists_submit_requests(req0, req1);
-
-	req0->elsp_submitted++;
-	if (req1)
-		req1->elsp_submitted++;
 }
 
 static bool execlists_check_remove_request(struct intel_engine_cs *ring,