[Intel-gfx] [PATCH 3/6] drm/atomic: Add ->atomic_check() hook for private objects

[Lyude Paul]

Currently; private objects are mostly used just for driver-specific
atomic state, but not entirely. MST also uses private objects for
holding it's atomic state, but in order to make our MST helpers safer
for atomic we need to be able to check that state after the driver has
performed it's own checks on the atomic state. So, add an optional
->atomic_check() callback into drm_private_state_funcs that gets called
after the driver's atomic checks.

Signed-off-by: Lyude Paul <lyude at redhat.com>
Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
---
 drivers/gpu/drm/drm_atomic.c | 14 ++++++++++++++
 include/drm/drm_atomic.h     | 16 ++++++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index 3dbfbddae7e6..2db9f219732b 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -966,6 +966,8 @@ int drm_atomic_check_only(struct drm_atomic_state *state)
 	struct drm_crtc_state *crtc_state;
 	struct drm_connector *conn;
 	struct drm_connector_state *conn_state;
+	struct drm_private_obj *priv_obj;
+	struct drm_private_state *priv_state;
 	int i, ret = 0;
 
 	DRM_DEBUG_ATOMIC("checking %p\n", state);
@@ -1007,6 +1009,18 @@ int drm_atomic_check_only(struct drm_atomic_state *state)
 		}
 	}
 
+	for_each_new_private_obj_in_state(state, priv_obj, priv_state, i) {
+		if (!priv_obj->funcs->atomic_check)
+			continue;
+
+		ret = priv_obj->funcs->atomic_check(priv_obj, priv_state);
+		if (ret) {
+			DRM_DEBUG_ATOMIC("[PRIVATE:%p] atomic check on state %p failed\n",
+					 priv_obj, priv_state);
+			return ret;
+		}
+	}
+
 	if (!state->allow_modeset) {
 		for_each_new_crtc_in_state(state, crtc, crtc_state, i) {
 			if (drm_atomic_crtc_needs_modeset(crtc_state)) {
diff --git a/include/drm/drm_atomic.h b/include/drm/drm_atomic.h
index f9b35834c45d..3e504eeb1122 100644
--- a/include/drm/drm_atomic.h
+++ b/include/drm/drm_atomic.h
@@ -216,6 +216,22 @@ struct drm_private_state_funcs {
 	 */
 	void (*atomic_destroy_state)(struct drm_private_obj *obj,
 				     struct drm_private_state *state);
+
+	/**
+	 * @atomic_check:
+	 *
+	 * Perform a check of the current state of the private object to
+	 * ensure that it's valid. This is an optional callback. If
+	 * implemented, it will be called after atomic checks have been
+	 * performed on all of the planes, CRTCs, connectors, and the new
+	 * &drm_mode_config in the atomic state.
+	 *
+	 * RETURNS:
+	 *
+	 * 0 on success, negative error code on failure.
+	 */
+	int (*atomic_check)(struct drm_private_obj *obj,
+			    struct drm_private_state *state);
 };
 
 /**
-- 
2.17.2