Async I/O on RT fifos

[Arnold Radtke <Arnold.Radtke@Ferrari.DE>]

We need asynchronious I/O of RT fifos. The RT kernel task writes data to
RT fifo and if data are available for Linux user mode process, we want
to have a SIGIO. We open RT fifo device with O_ASYNC or do fcntl with
O_ASYNC. I had a look to the source of  rtl_fifo.c and I think this
feature is not yet implemented. Is there a easy patch to change the code
for async I/O ? or better it's possible to implement it generally?

Thanks.

Arnold