In drm_atomic_helper_check_crtc_state(), do not add a new plane state
to the global state if it does not exist already. Adding a new plane
state will result in overhead for the plane during the atomic-commit
step.

For the test in drm_atomic_helper_check_crtc_state() to succeed, it is
important that the CRTC has an enabled primary plane after the commit.
This can be a newly enabled plane or an already enabled plane. So if a
plane is not part of the commit, use the plane's existing state.

v2:
        * remove unnecessary test for plane->crtc (Ville)
        * inline drm_atomic_get_next_plane_state() (Ville)
        * acquire plane lock before accessing plane->state (Ville)

Signed-off-by: Thomas Zimmermann <[email protected]>
Fixes: d6b9af1097fe ("drm/atomic-helper: Add helper 
drm_atomic_helper_check_crtc_state()")
Cc: Thomas Zimmermann <[email protected]>
Cc: Jocelyn Falempe <[email protected]>
Cc: Maarten Lankhorst <[email protected]>
Cc: Maxime Ripard <[email protected]>
Cc: David Airlie <[email protected]>
Cc: Daniel Vetter <[email protected]>
Cc: [email protected]
---
 drivers/gpu/drm/drm_atomic_helper.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/drm_atomic_helper.c 
b/drivers/gpu/drm/drm_atomic_helper.c
index 98cc3137c062..b7774a39712b 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -960,10 +960,18 @@ int drm_atomic_helper_check_crtc_state(struct 
drm_crtc_state *crtc_state,
 
                        if (plane->type != DRM_PLANE_TYPE_PRIMARY)
                                continue;
-                       plane_state = drm_atomic_get_plane_state(state, plane);
-                       if (IS_ERR(plane_state))
-                               return PTR_ERR(plane_state);
-                       if (plane_state->fb && plane_state->crtc) {
+
+                       plane_state = drm_atomic_get_new_plane_state(state, 
plane);
+                       if (!plane_state) {
+                               /* plane isn't part of the update; look at 
existing state */
+                               int ret = drm_modeset_lock(&plane->mutex, 
state->acquire_ctx);
+
+                               if (ret)
+                                       return ret;
+                               plane_state = plane->state;
+                       }
+
+                       if (plane_state->fb) {
                                has_primary_plane = true;
                                break;
                        }
-- 
2.37.3

Reply via email to