drm/i915: Only emit flushes on active rings.

This avoids the excess flush and requests on idle rings (and spamming
the debug log ;-)

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Eric Anholt <eric@anholt.net>

drivers/gpu/drm/i915/i915_drv.h

@@ -285,6 +285,9 @@ typedef struct drm_i915_private {
 	unsigned int sr01, adpa, ppcr, dvob, dvoc, lvds;
 	int vblank_pipe;
 	int num_pipe;
+	u32 flush_rings;
+#define FLUSH_RENDER_RING	0x1
+#define FLUSH_BSD_RING		0x2
 
 	/* For hangcheck timer */
 #define DRM_I915_HANGCHECK_PERIOD 75 /* in jiffies */

drivers/gpu/drm/i915/i915_gem.c

@@ -3117,6 +3117,7 @@ static void
 i915_gem_object_set_to_gpu_domain(struct drm_gem_object *obj)
 {
 	struct drm_device		*dev = obj->dev;
+	drm_i915_private_t		*dev_priv = dev->dev_private;
 	struct drm_i915_gem_object	*obj_priv = to_intel_bo(obj);
 	uint32_t			invalidate_domains = 0;
 	uint32_t			flush_domains = 0;
@@ -3179,6 +3180,13 @@ i915_gem_object_set_to_gpu_domain(struct drm_gem_object *obj)
 		obj->pending_write_domain = obj->write_domain;
 	obj->read_domains = obj->pending_read_domains;
 
+	if (flush_domains & I915_GEM_GPU_DOMAINS) {
+		if (obj_priv->ring == &dev_priv->render_ring)
+			dev_priv->flush_rings |= FLUSH_RENDER_RING;
+		else if (obj_priv->ring == &dev_priv->bsd_ring)
+			dev_priv->flush_rings |= FLUSH_BSD_RING;
+	}
+
 	dev->invalidate_domains |= invalidate_domains;
 	dev->flush_domains |= flush_domains;
 #if WATCH_BUF
@@ -3718,7 +3726,6 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data,
 		ring = &dev_priv->render_ring;
 	}
 
-
 	if (args->buffer_count < 1) {
 		DRM_ERROR("execbuf with %d buffers\n", args->buffer_count);
 		return -EINVAL;
@@ -3892,6 +3899,7 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data,
 	 */
 	dev->invalidate_domains = 0;
 	dev->flush_domains = 0;
+	dev_priv->flush_rings = 0;
 
 	for (i = 0; i < args->buffer_count; i++) {
 		struct drm_gem_object *obj = object_list[i];
@@ -3912,16 +3920,14 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data,
 		i915_gem_flush(dev,
 			       dev->invalidate_domains,
 			       dev->flush_domains);
-		if (dev->flush_domains & I915_GEM_GPU_DOMAINS) {
+		if (dev_priv->flush_rings & FLUSH_RENDER_RING)
 			(void)i915_add_request(dev, file_priv,
-					dev->flush_domains,
-					&dev_priv->render_ring);
-
-			if (HAS_BSD(dev))
-				(void)i915_add_request(dev, file_priv,
-						dev->flush_domains,
-						&dev_priv->bsd_ring);
-		}
+					       dev->flush_domains,
+					       &dev_priv->render_ring);
+		if (dev_priv->flush_rings & FLUSH_BSD_RING)
+			(void)i915_add_request(dev, file_priv,
+					       dev->flush_domains,
+					       &dev_priv->bsd_ring);
 	}
 
 	for (i = 0; i < args->buffer_count; i++) {