drm/i915: Don't return busy for buffers left on the flushing list.

These buffers don't have active rendering still occurring to them, they just
need either a flush to be emitted or a retire_requests to occur so that we
notice they're done.  Return unbusy so that one of the two occurs.  The two
expected consumers of this interface (OpenGL and libdrm_intel BO cache) both
want this behavior.

Signed-off-by: Eric Anholt <eric@anholt.net>
Acked-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index ad672d8548289b8e7a934123d2ff4878f272b6e0..24fe8c10b4b22c6bac1cfa17d79d55f02dd59179 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2309,7 +2309,14 @@ i915_gem_busy_ioctl(struct drm_device *dev, void *data,
        }
 
        obj_priv = obj->driver_private;
-       args->busy = obj_priv->active;
+       /* Don't count being on the flushing list against the object being
+        * done.  Otherwise, a buffer left on the flushing list but not getting
+        * flushed (because nobody's flushing that domain) won't ever return
+        * unbusy and get reused by libdrm's bo cache.  The other expected
+        * consumer of this interface, OpenGL's occlusion queries, also specs
+        * that the objects get unbusy "eventually" without any interference.
+        */
+       args->busy = obj_priv->active && obj_priv->last_rendering_seqno != 0;
 
        drm_gem_object_unreference(obj);
        mutex_unlock(&dev->struct_mutex);