[PATCH 02/18] drm: Add a new helper to validate damage during atomic_check

[Deepak Rawat]

This helper function makes sure that damage from plane state is
discarded for full modeset cycle. For some reason, which makes damage
irrelevant, driver might want to do a full plane update for e.g. full
modeset. Such cases must be checked here.

Note: In the previous version of the patch the name was clear damage.
IMO the new name check_plane_damage() make more sense as this function
really will be validating if need to discard damage.

Cc: ville.syrjala at linux.intel.com
Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
Cc: Pekka Paalanen <ppaalanen at gmail.com>
Signed-off-by: Deepak Rawat <drawat at vmware.com>
---
 drivers/gpu/drm/drm_atomic_helper.c |  3 +++
 drivers/gpu/drm/drm_damage_helper.c | 38 +++++++++++++++++++++++++++++
 include/drm/drm_damage_helper.h     |  2 ++
 3 files changed, 43 insertions(+)

diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 280ae5bc4753..9f89a801dbf0 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -32,6 +32,7 @@
 #include <drm/drm_crtc_helper.h>
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_writeback.h>
+#include <drm/drm_damage_helper.h>
 #include <linux/dma-fence.h>
 
 #include "drm_crtc_helper_internal.h"
@@ -828,6 +829,8 @@ drm_atomic_helper_check_planes(struct drm_device *dev,
 
 		drm_atomic_helper_plane_changed(state, old_plane_state, new_plane_state, plane);
 
+		drm_atomic_helper_check_plane_damage(state, new_plane_state);
+
 		if (!funcs || !funcs->atomic_check)
 			continue;
 
diff --git a/drivers/gpu/drm/drm_damage_helper.c b/drivers/gpu/drm/drm_damage_helper.c
index 8dc906a489a9..c130514bbb21 100644
--- a/drivers/gpu/drm/drm_damage_helper.c
+++ b/drivers/gpu/drm/drm_damage_helper.c
@@ -29,6 +29,7 @@
  *
  **************************************************************************/
 
+#include <drm/drm_atomic.h>
 #include <drm/drm_damage_helper.h>
 
 /**
@@ -81,3 +82,40 @@ void drm_plane_enable_fb_damage_clips(struct drm_plane *plane)
 				   0);
 }
 EXPORT_SYMBOL(drm_plane_enable_fb_damage_clips);
+
+/**
+ * drm_atomic_helper_check_plane_damage - Verify plane damage on atomic_check.
+ * @state: The driver state object.
+ * @plane_state: Plane state for which to verify damage.
+ *
+ * This helper function makes sure that damage from plane state is discarded
+ * for full modeset cycle. For some reason, which makes damage irrelevant,
+ * driver might want to do a full plane update for e.g. full modeset. Such
+ * cases must be checked here. Note that NULL &drm_plane_state.fb_damage_clips
+ * in plane state means that full update should happen. It also ensue helper
+ * iterator to return &drm_plane_state.src as damage.
+ *
+ * Currently this helper discard damage during full modeset only. This is
+ * because, presently only vmwgfx exposes damage interface, which need full
+ * plane update during full modeset only. As more driver add damage support,
+ * should any state change need full plane update, must be added here.
+ */
+void drm_atomic_helper_check_plane_damage(struct drm_atomic_state *state,
+					  struct drm_plane_state *plane_state)
+{
+	struct drm_crtc_state *crtc_state;
+
+	if (plane_state->crtc) {
+		crtc_state = drm_atomic_get_new_crtc_state(state,
+							   plane_state->crtc);
+
+		if (WARN_ON(!crtc_state))
+			return;
+
+		if (drm_atomic_crtc_needs_modeset(crtc_state)) {
+			drm_property_blob_put(plane_state->fb_damage_clips);
+			plane_state->fb_damage_clips = NULL;
+		}
+	}
+}
+EXPORT_SYMBOL(drm_atomic_helper_check_plane_damage);
diff --git a/include/drm/drm_damage_helper.h b/include/drm/drm_damage_helper.h
index 4947c614fff9..59584cbf3d40 100644
--- a/include/drm/drm_damage_helper.h
+++ b/include/drm/drm_damage_helper.h
@@ -35,5 +35,7 @@
 #include <drm/drm_atomic_helper.h>
 
 void drm_plane_enable_fb_damage_clips(struct drm_plane *plane);
+void drm_atomic_helper_check_plane_damage(struct drm_atomic_state *state,
+					  struct drm_plane_state *plane_state);
 
 #endif
-- 
2.17.1