vivid_output_is_connected_to
if (vivid_output_is_connected_to(dev)) {
struct vivid_dev *dev_rx = vivid_output_is_connected_to(dev);
struct vivid_dev *vivid_output_is_connected_to(struct vivid_dev *dev);
struct vivid_dev *in_dev = vivid_output_is_connected_to(dev);