VIDIOC_OVERLAY
v4l2_disable_ioctl(&dev->vid_out_dev, VIDIOC_OVERLAY);
SET_VALID_IOCTL(ops, VIDIOC_OVERLAY, vidioc_overlay);
IOCTL_INFO(VIDIOC_OVERLAY, v4l_overlay, v4l_print_u32, INFO_FL_PRIO),