drm/i915: pin sprite fb only if it changed

Optimize code avoiding helding dev mutex if old fb and current fb
are the same.

v2: take Ville's comments
	- move comment along with the pin_and_fence call
	- check for error before calling i915_gem_track_fb
	- move old_obj != obj to an upper if condition

Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/intel_sprite.c b/drivers/gpu/drm/i915/intel_sprite.c
index a4306cf..90bb45f 100644 (file)
--- a/drivers/gpu/drm/i915/intel_sprite.c
+++ b/drivers/gpu/drm/i915/intel_sprite.c
@@ -1038,21 +1038,24 @@ intel_commit_sprite_plane(struct drm_plane *plane,
        primary_enabled = !drm_rect_equals(dst, clip) || colorkey_enabled(intel_plane);
        WARN_ON(!primary_enabled && !state->visible && intel_crtc->active);
 
-       mutex_lock(&dev->struct_mutex);
-
-       /* Note that this will apply the VT-d workaround for scanouts,
-        * which is more restrictive than required for sprites. (The
-        * primary plane requires 256KiB alignment with 64 PTE padding,
-        * the sprite planes only require 128KiB alignment and 32 PTE padding.
-        */
-       ret = intel_pin_and_fence_fb_obj(dev, obj, NULL);
 
-       i915_gem_track_fb(old_obj, obj,
-                         INTEL_FRONTBUFFER_SPRITE(pipe));
-       mutex_unlock(&dev->struct_mutex);
+       if (old_obj != obj) {
+               mutex_lock(&dev->struct_mutex);
 
-       if (ret)
-               return ret;
+               /* Note that this will apply the VT-d workaround for scanouts,
+                * which is more restrictive than required for sprites. (The
+                * primary plane requires 256KiB alignment with 64 PTE padding,
+                * the sprite planes only require 128KiB alignment and 32 PTE
+                * padding.
+                */
+               ret = intel_pin_and_fence_fb_obj(dev, obj, NULL);
+               if (ret == 0)
+                       i915_gem_track_fb(old_obj, obj,
+                                         INTEL_FRONTBUFFER_SPRITE(pipe));
+               mutex_unlock(&dev->struct_mutex);
+               if (ret)
+                       return ret;
+       }
 
        intel_plane->crtc_x = state->orig_dst.x1;
        intel_plane->crtc_y = state->orig_dst.y1;
@@ -1099,14 +1102,15 @@ intel_commit_sprite_plane(struct drm_plane *plane,
        }
 
        /* Unpin old obj after new one is active to avoid ugliness */
-       if (old_obj) {
+       if (old_obj && old_obj != obj) {
+
                /*
                 * It's fairly common to simply update the position of
                 * an existing object.  In that case, we don't need to
                 * wait for vblank to avoid ugliness, we only need to
                 * do the pin & ref bookkeeping.
                 */
-               if (old_obj != obj && intel_crtc->active)
+               if (intel_crtc->active)
                        intel_wait_for_vblank(dev, intel_crtc->pipe);
 
                mutex_lock(&dev->struct_mutex);