My problem of I/O port
doebel at os.inf.tu-dresden.de
Wed Sep 2 11:46:31 CEST 2009
-----BEGIN PGP SIGNED MESSAGE-----
> And I have some questions to ask:
> 1. I used the l4linux-2.6.30 kernel, now to booting it besides
> fiasco default config, there is
> [ *] Enable I/O port protection
> feature must need, isn't it?
> It not needed in l4linux-2.6.23 kernel or earlier.
This is not a Linux feature, but one from the Fiasco kernel. You should
have it enabled by default. It basically prevents applications from
accessing I/O ports unless they are the first to access these.
Otherwise, your application needs to get them mapped (using an I/O
flexpage) from an application that has access to the IO/ ports.
> 2. Will this feature prevent the other server to access to the io
> I seems meeting this problem, my parport server(#b) want to
> access the port 077a, but system say the owner is #a(l4io), even I set the
> parport priority higher than l4io, it also the same problem. the last error
> message is like follow:
> server | <6>parport0: PC-style at 0x378 [PCSPP,TRISTATE]
> server | <6>parport0: irq 7 detected
> ROOT: Cannot send port 077a to task #0b, owner is #a
> ROOT: task B.00 at 01804299 is trying to get I/O port 077a
> allocated by task 0b.
What are tasks A and B? Assuming A is your parport server and B is L4IO,
then you need to call l4io_request_region() to retrieve the ports you
want to access from L4IO. As your parport server is DDE-based you can
also do this using Linux' means (request_region()).
> How can I do could make the parport server run together with the
> l4linux, or to make it could access the port it needed?
I don't see where L4Linux comes into play here?
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.9 (GNU/Linux)
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org
-----END PGP SIGNATURE-----
More information about the l4-hackers