[PATCH v3] drm/i915/display: Handle struct drm_plane_state.ignore_damage_clips

Call drm_atomic_helper_check_plane_damage() in plane_atomic_check()
before copying the damage information to guarantees that ignore_damage_clips
from struct drm_plane_state has the correct value. Although i915 does not
directly modify or use the flag, DRM's damage iterator will soon rely on
it.

As a side effect, if the CRTC has been marked for a full modeset before
the call to drm_atomic_helper_check_plane_damage() happens, the plane now
ignores all damage clips and does a full update.

Git commit 35ed38d58257 ("drm: Allow drivers to indicate the damage
helpers to ignore damage clips") introduced ignore_damage_clips to
selectively ignore damage clipping for certain framebuffer changes. The
mode-setting pipeline can disabled damage clippings for an atomic commit
by setting ignore_damage_clips in struct drm_plane_state. The atomic
commit will then do a full display update.

Future directions: there's currently a multitude of options that affect
damage clipping; with different places seeing different state. In order
to unify this, drm_atomic_helper_check_plane_state() will soon evaluate
all options in a single place and set ignore_damage_clips accordingly. All
later stages of the mode-setting pipeline will only look at this field.

v3:
- fix the call to drm_atomic_helper_check_plane_state()
- use primary-CRTC's plane state (Sashiko)
- note full-plane updates in commit description
v2:
- move _check_plane_damage() before reading damage first time (Sashiko)
- expand commit description

Signed-off-by: Thomas Zimmermann <[email protected]>
Reviewed-by: Javier Martinez Canillas <[email protected]>
---
Taken with updates from the series at

  https://lore.kernel.org/dri-devel/[email protected]/
---
 drivers/gpu/drm/i915/display/intel_plane.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/display/intel_plane.c b/drivers/gpu/drm/i915/display/intel_plane.c
index a440f92ff00c..d64f151ce410 100644
--- a/drivers/gpu/drm/i915/display/intel_plane.c
+++ b/drivers/gpu/drm/i915/display/intel_plane.c
@@ -850,7 +850,7 @@ static int plane_atomic_check(struct intel_atomic_state *state,
 		intel_atomic_get_new_plane_state(state, plane);
 	const struct intel_plane_state *old_plane_state =
 		intel_atomic_get_old_plane_state(state, plane);
-	const struct intel_plane_state *new_primary_crtc_plane_state;
+	struct intel_plane_state *new_primary_crtc_plane_state;
 	const struct intel_plane_state *old_primary_crtc_plane_state;
 	struct intel_crtc *crtc = intel_crtc_for_pipe(display, plane->pipe);
 	const struct intel_crtc_state *old_crtc_state =
@@ -873,6 +873,14 @@ static int plane_atomic_check(struct intel_atomic_state *state,
 		old_primary_crtc_plane_state = old_plane_state;
 	}
 
+	/*
+	 * Prepare plane-damage state before using it; do this on all
+	 * display versions to keep the underlying DRM plane state in
+	 * good shape.
+	 */
+	drm_atomic_helper_check_plane_damage(&state->base,
+					     &new_primary_crtc_plane_state->uapi);
+
 	intel_plane_copy_uapi_plane_damage(new_plane_state,
 					   old_primary_crtc_plane_state,
 					   new_primary_crtc_plane_state);

base-commit: fcaba3bc017906059b910ece3f83185e93010581
prerequisite-patch-id: c67e5d886a47b7d0266d81100837557fda34cb24
prerequisite-patch-id: a5a973e527c88a5b47053d7a72aefe0b550197cb
prerequisite-patch-id: b9adc9622920a3e70168e672c2c92795b3e3a106
prerequisite-patch-id: 5030de433a01c2e99056cadb676a8e2ba35f055a
-- 
2.54.0