From owner-freebsd-hackers@FreeBSD.ORG  Fri Aug 22 20:02:46 2008
Return-Path: <owner-freebsd-hackers@FreeBSD.ORG>
Delivered-To: freebsd-hackers@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id 279D81065676
	for <freebsd-hackers@freebsd.org>; Fri, 22 Aug 2008 20:02:46 +0000 (UTC)
	(envelope-from pb@ludd.ltu.se)
Received: from mother.ludd.ltu.se (mother.ludd.ltu.se [130.240.16.3])
	by mx1.freebsd.org (Postfix) with ESMTP id AA2F98FC08
	for <freebsd-hackers@freebsd.org>; Fri, 22 Aug 2008 20:02:45 +0000 (UTC)
	(envelope-from pb@ludd.ltu.se)
Received: from brother.ludd.ltu.se (root@brother.ludd.ltu.se [130.240.16.78])
	by mother.ludd.ltu.se (8.13.6+Sun/8.12.10) with ESMTP id
	m7MK2fgY000072 for <freebsd-hackers@freebsd.org>;
	Fri, 22 Aug 2008 22:02:41 +0200 (MEST)
Received: from brother.ludd.ltu.se (pb@localhost [127.0.0.1])
	by brother.ludd.ltu.se (8.13.6+Sun/8.12.2) with ESMTP id m7MK2fUI004488
	for <freebsd-hackers@freebsd.org>;
	Fri, 22 Aug 2008 22:02:41 +0200 (MEST)
Received: (from pb@localhost)
	by brother.ludd.ltu.se (8.13.6+Sun/8.13.6/Submit) id m7MK2fvo004486
	for freebsd-hackers@freebsd.org; Fri, 22 Aug 2008 22:02:41 +0200 (MEST)
From: Peter B <pb@ludd.ltu.se>
Message-Id: <200808222002.m7MK2fvo004486@brother.ludd.ltu.se>
To: freebsd-hackers@freebsd.org
Date: Fri, 22 Aug 2008 22:02:41 +0200 (MEST)
X-Mailer: ELM [version 2.5 PL6]
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
X-Mailman-Approved-At: Fri, 22 Aug 2008 20:08:46 +0000
Subject: usb match() function
X-BeenThere: freebsd-hackers@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Technical Discussions relating to FreeBSD
	<freebsd-hackers.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hackers>, 
	<mailto:freebsd-hackers-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-hackers>
List-Post: <mailto:freebsd-hackers@freebsd.org>
List-Help: <mailto:freebsd-hackers-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hackers>,
	<mailto:freebsd-hackers-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Fri, 22 Aug 2008 20:02:46 -0000


Within the usb drivers (/usr/src/sys/dev/usb/u*.c) there's an matching routine
where the 'uaa->iface' is supposed to be assigned before the routine is called.

However for a new device or class this doesn't seem to work. Instead 'uaa'
is set like for an generic device (two interfaces, no "default" in my case).

So how is one supposed to make the kernel fill in 'uaa->iface' ..?

Code excerpt (v7.x):
  static int
  *_match(device_t self)
  {
        struct usb_attach_arg *uaa = device_get_ivars(self);
        usb_interface_descriptor_t *id;

        DPRINTFN(10,("*_match\n"));
        if (uaa->iface == NULL)
                return (UMATCH_NONE);