Subject: Re: Various NetBSD kernel questions to help with port of FreeBSD
To: David Young <dyoung@pobox.com>
From: Jeff Rizzo <riz@redcrowgroup.com>
List: tech-kern
Date: 11/08/2004 11:42:01
David Young wrote:
>
>I would ask of the original poster, does the Asterisk architecture
>observe this policy/mechanism, userland/kernel split?
>
>(I am dimly aware that STREAMS has something to do with all of this.)
>
>
>
Well, I find myself in the somewhat uncomfortable position of learning
about this as I'm doing it. :) From what I can see, it does indeed
keep out of the original audio stream as much as possible.
One of the things that's clear to me is that the current architecture of
the driver, however well it works under Linux, is probably not ideal for
NetBSD. However, until such time as I know a lot more about asterisk
and the specific hardware, I can't really contemplate doing a redesign
of the driver architecture, so what I'm concentrating on at the moment
is understanding what's there and why it's done that way, and how best
to fit the current architecture into NetBSD. Since the drivers I'm
working with are GPL-tainted anyway, it's not like they're going to wind
up in the NetBSD tree anyway; perhaps a rearchitected version could.
Assuming it's still something I'm interested in once I get it working in
its current form, I'll consider undertaking that, but like a lot of the
rest of you, this isn't something I'm being paid to do, so we'll see how
long my enthusiam lasts after I get a dial tone. :-)
One thing I have learned since I made the original post: apparently,
Linux open() calls have per-descriptor private data for the device; the
FreeBSD port goes to some pains to emulate this by redefining file
operations for a new descriptor and setting the f_data field of 'struct
file' to point to this device-private data... I'm understanding a little
better what that's about, and am noodling over how to make that work in
NetBSD.
Thanks a lot for all the discussion on the topic - it's something I'm
currently very interested in.
+j
--
Jeff Rizzo riz@redcrowgroup.com
Red Crow Group LLC http://www.redcrowgroup.com/
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