Re: [uml-devel] Driver development questions.

[johan v. <joh...@pa...>]

'lo greg, jeff,

Greg Lonnon wrote:
> >> Further, I also tried to use the fd/interrupt thingie, but that did
> >> not work. The fd gets the (POLLOUT | POLLWRNORM) events set. It seems
> >> the interrupt simulation does not respond to that.
> 
> Are you doing writes to a file.  Looking at the events, it looks like
> you are trying to write.  Are you checking the return codes and the
> errno to insure the write was complete (look at the
> eth_user.c:nb_write() for an example).

I have written to a file before you know ;)
Seriously, I was not writing to a file, I was doing ioctl's.
The problem is partly that I was not calling activate_fd(). I looked at it's code and I don't think
I can use it. I have no idea whether fcntl will work. I will try.
I prefer another solution though. I have an alternative way to get a signal delivered when I want my
irq, but the fd will have (POLLOUT | POLLWRNORM) set and nothing else, so I guess that will not
trigger the select(). I will also have to implement a link_fd() or something that is basically
active_fd() without the fcntl's.

Also, if you would consider to add the 'writable'-event to the irq code, wouldn't it be more usefull
to use poll() iso select() and have the user supply the flags to um_request_irq() or to
activate_fd()? It would add a lot of flexibility and little overhead (although it will use more
memory for the poll structs).
If you want, I'll write the code.

Sorry to be a bit mysterious, but I would like to keep whatever I am working on under wraps until it
is at least partially functional.

thanks,
	J.