drm: Add a new plane property to send damage during plane update

FB_DAMAGE_CLIPS is an optional plane property to mark damaged regions
on the plane in framebuffer coordinates of the framebuffer attached to
the plane.

The layout of blob data is simply an array of "struct drm_mode_rect".
Unlike plane src coordinates, damage clips are not in 16.16 fixed point.
As plane src in framebuffer cannot be negative so are damage clips. In
damage clip, x1/y1 are inclusive and x2/y2 are exclusive.

This patch also exports the kernel internal drm_rect to userspace as
drm_mode_rect. This is because "struct drm_clip_rect" is not sufficient
to represent damage for current plane size.

Driver which are interested in enabling FB_DAMAGE_CLIPS property for a
plane should enable this property using drm_plane_enable_damage_clips.

v2:
- Input validation on damage clips against framebuffer size.
- Doc update, other minor changes.

Signed-off-by: Lukasz Spintzyk <lukasz.spintzyk@displaylink.com>
Signed-off-by: Deepak Rawat <drawat@vmware.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>

1 files changed, 22 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index 9ac26437051b..48ec378fb27e 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -531,6 +531,8 @@ static int drm_atomic_plane_check(const struct drm_plane_state *old_plane_state,
 	struct drm_crtc *crtc = new_plane_state->crtc;
 	const struct drm_framebuffer *fb = new_plane_state->fb;
 	unsigned int fb_width, fb_height;
+	struct drm_mode_rect *clips;
+	uint32_t num_clips;
 	int ret;
 
 	/* either *both* CRTC and FB must be set, or neither */
@@ -604,6 +606,26 @@ static int drm_atomic_plane_check(const struct drm_plane_state *old_plane_state,
 		return -ENOSPC;
 	}
 
+	clips = drm_plane_get_damage_clips(new_plane_state);
+	num_clips = drm_plane_get_damage_clips_count(new_plane_state);
+
+	/* Make sure damage clips are valid and inside the fb. */
+	while (num_clips > 0) {
+		if (clips->x1 >= clips->x2 ||
+		    clips->y1 >= clips->y2 ||
+		    clips->x1 < 0 ||
+		    clips->y1 < 0 ||
+		    clips->x2 > fb_width ||
+		    clips->y2 > fb_height) {
+			DRM_DEBUG_ATOMIC("[PLANE:%d:%s] invalid damage clip %d %d %d %d\n",
+					 plane->base.id, plane->name, clips->x1,
+					 clips->y1, clips->x2, clips->y2);
+			return -EINVAL;
+		}
+		clips++;
+		num_clips--;
+	}
+
 	if (plane_switching_crtc(old_plane_state, new_plane_state)) {
 		DRM_DEBUG_ATOMIC("[PLANE:%d:%s] switching CRTC directly\n",
 				 plane->base.id, plane->name);