static int v4l2loopback_s_ctrl(struct v4l2_ctrl *ctrl)
{
	struct v4l2_loopback_device *dev = container_of(ctrl->handler, struct v4l2_loopback_device, ctrl_handler);
	return v4l2loopback_set_ctrl(dev, ctrl->id, ctrl->val);
}
static int v4l2loopback_s_ctrl(struct v4l2_ctrl *ctrl)
{
	struct v4l2_loopback_device *dev = container_of(ctrl->handler, struct v4l2_loopback_device, ctrl_handler);
	return v4l2loopback_set_ctrl(dev, ctrl->id, ctrl->val);
}