static int uio_fasync(int fd, struct file *filep, int on)
{
	struct uio_listener *listener = filep->private_data;
	struct uio_device *idev = listener->dev;

	return fasync_helper(fd, filep, on, &idev->async_queue);
}
static int uio_fasync(int fd, struct file *filep, int on)
{
	struct uio_listener *listener = filep->private_data;
	struct uio_device *idev = listener->dev;

	return fasync_helper(fd, filep, on, &idev->async_queue);
}