drm/atomic-helper: Implement drm_atomic_helper_duplicate_state()
This function can be used to duplicate an atomic state object. This is
useful for example to implement suspend/resume, where the state before
suspend can be saved and restored upon resume.
v2: move locking to caller, be more explicit about prerequisites
v3: explicitly pass lock acquisition context, improve kerneldoc
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 77d55a9..9941167 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -2372,6 +2372,84 @@
EXPORT_SYMBOL(drm_atomic_helper_connector_duplicate_state);
/**
+ * drm_atomic_helper_duplicate_state - duplicate an atomic state object
+ * @dev: DRM device
+ * @ctx: lock acquisition context
+ *
+ * Makes a copy of the current atomic state by looping over all objects and
+ * duplicating their respective states.
+ *
+ * Note that this treats atomic state as persistent between save and restore.
+ * Drivers must make sure that this is possible and won't result in confusion
+ * or erroneous behaviour.
+ *
+ * Note that if callers haven't already acquired all modeset locks this might
+ * return -EDEADLK, which must be handled by calling drm_modeset_backoff().
+ *
+ * Returns:
+ * A pointer to the copy of the atomic state object on success or an
+ * ERR_PTR()-encoded error code on failure.
+ */
+struct drm_atomic_state *
+drm_atomic_helper_duplicate_state(struct drm_device *dev,
+ struct drm_modeset_acquire_ctx *ctx)
+{
+ struct drm_atomic_state *state;
+ struct drm_connector *conn;
+ struct drm_plane *plane;
+ struct drm_crtc *crtc;
+ int err = 0;
+
+ state = drm_atomic_state_alloc(dev);
+ if (!state)
+ return ERR_PTR(-ENOMEM);
+
+ state->acquire_ctx = ctx;
+
+ drm_for_each_crtc(crtc, dev) {
+ struct drm_crtc_state *crtc_state;
+
+ crtc_state = drm_atomic_get_crtc_state(state, crtc);
+ if (IS_ERR(crtc_state)) {
+ err = PTR_ERR(crtc_state);
+ goto free;
+ }
+ }
+
+ drm_for_each_plane(plane, dev) {
+ struct drm_plane_state *plane_state;
+
+ plane_state = drm_atomic_get_plane_state(state, plane);
+ if (IS_ERR(plane_state)) {
+ err = PTR_ERR(plane_state);
+ goto free;
+ }
+ }
+
+ drm_for_each_connector(conn, dev) {
+ struct drm_connector_state *conn_state;
+
+ conn_state = drm_atomic_get_connector_state(state, conn);
+ if (IS_ERR(conn_state)) {
+ err = PTR_ERR(conn_state);
+ goto free;
+ }
+ }
+
+ /* clear the acquire context so that it isn't accidentally reused */
+ state->acquire_ctx = NULL;
+
+free:
+ if (err < 0) {
+ drm_atomic_state_free(state);
+ state = ERR_PTR(err);
+ }
+
+ return state;
+}
+EXPORT_SYMBOL(drm_atomic_helper_duplicate_state);
+
+/**
* __drm_atomic_helper_connector_destroy_state - release connector state
* @connector: connector object
* @state: connector state object to release