[Intel-gfx] [PATCH 02/13] drm/i915: allow lazy emitting of requests

[Daniel Vetter]

Sometimes (like when flushing in preparation of batchbuffer execution)
we know that we'll emit a request but haven't yet done so. Allow this
case by simply taking the next seqno by default. Ensure that a request
is eventually emitted before waiting for an object by BUG'ing in
i915_gem_object_wait_rendering.

Also replace one open-coded version of i915_gem_object_wait_rendering,
to prevent future code-diversion.

This will be used for pipelined fencing, for otherwise we'd need to emit
up to num_fences_used additional request per execbuf ioctl.

Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
---
 drivers/gpu/drm/i915/i915_gem.c |   19 +++++++++----------
 1 files changed, 9 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index bb3c491..3c0bf2c 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1517,6 +1517,9 @@ i915_gem_object_move_to_active(struct drm_gem_object *obj, uint32_t seqno)
 		drm_gem_object_reference(obj);
 		obj_priv->active = 1;
 	}
+	/* Take the seqno of the next request if none is given */
+	if (seqno == 0)
+		seqno = dev_priv->mm.next_gem_seqno;
 	/* Move from whatever list we were on to the tail of execution. */
 	spin_lock(&dev_priv->mm.active_list_lock);
 	list_move_tail(&obj_priv->list,
@@ -1992,6 +1995,7 @@ static int
 i915_gem_object_wait_rendering(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 = obj->driver_private;
 	int ret;
 
@@ -2004,6 +2008,8 @@ i915_gem_object_wait_rendering(struct drm_gem_object *obj)
 	 * it.
 	 */
 	if (obj_priv->active) {
+		BUG_ON(obj_priv->last_rendering_seqno
+				== dev_priv->mm.next_gem_seqno);
 #if WATCH_BUF
 		DRM_INFO("%s: object %p wait for seqno %08x\n",
 			  __func__, obj, obj_priv->last_rendering_seqno);
@@ -2895,17 +2901,10 @@ i915_gem_object_set_to_display_plane(struct drm_gem_object *obj)
 		return -EINVAL;
 
 	i915_gem_object_flush_gpu_write_domain(obj);
-
 	/* Wait on any GPU rendering and flushing to occur. */
-	if (obj_priv->active) {
-#if WATCH_BUF
-		DRM_INFO("%s: object %p wait for seqno %08x\n",
-			  __func__, obj, obj_priv->last_rendering_seqno);
-#endif
-		ret = i915_do_wait_request(dev, obj_priv->last_rendering_seqno, 0);
-		if (ret != 0)
-			return ret;
-	}
+	ret = i915_gem_object_wait_rendering(obj);
+	if (ret != 0)
+		return ret;
 
 	old_write_domain = obj->write_domain;
 	old_read_domains = obj->read_domains;
-- 
1.6.6.1