poll_wait(file, &write_subdev->async->wait_head, wait);
comedi_buf_write_alloc(write_subdev->async,
write_subdev->async->prealloc_bufsz);
poll_wait(file, &write_subdev->async->wait_head, wait);
comedi_buf_write_alloc(write_subdev->async,
write_subdev->async->prealloc_bufsz);