freebsd stable - Jan 2008 - USB prevents system from powering off and ucom prevents usb from being unloaded - ideas?

Subject line is the executive summary of my problem:

I have a box with an Intel 945GC A2 chipset that will not poweroff on shutdown 
if the usb kernel module is loaded (or statically compiled into the kernel). 
Unloading the usb kernel modules sometime during shutdown (I hacked the usbd 
rc script for this) to work around the problem helped until I needed to hook 
up another device which uses ucom(4) to the machine. On kldunload, ucom 
claims to detach, but remains loaded and subsequent kldunload attempts 
trigger the error "kldunload: attempt to unload file that was loaded by the
kernel". The stuck ucom in turn prevents usb from getting unloaded and the 
machine cannot poweroff.

I have already tried disabling EHCI, but it does not help. Any ideas on either 
getting uhci to properly detach on shutdown or getting rid of ucom?


Cheers,
-- 
   ,_,   | Michael Nottebrock               | lofi@freebsd.org
 (/^ ^\) | FreeBSD - The Power to Serve     | http://www.freebsd.org
   \u/   | K Desktop Environment on FreeBSD | http://freebsd.kde.org
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Hi, Michael

Please try attached patch for current.
For other branches, please get a patch from

  http://people.freebsd.org/~akiyama/patches/

I've only tested it on RELENG_6 branch, but it would work for both
current and RELENG_7.

Regards,

At Wed, 16 Jan 2008 17:08:34 +0100,
Michael Nottebrock wrote:
> 
> [1  <text/plain; us-ascii (quoted-printable)>]
> Subject line is the executive summary of my problem:
> 
> I have a box with an Intel 945GC A2 chipset that will not poweroff on
shutdown
> if the usb kernel module is loaded (or statically compiled into the
kernel).
> Unloading the usb kernel modules sometime during shutdown (I hacked the
usbd
> rc script for this) to work around the problem helped until I needed to
hook
> up another device which uses ucom(4) to the machine. On kldunload, ucom 
> claims to detach, but remains loaded and subsequent kldunload attempts 
> trigger the error "kldunload: attempt to unload file that was loaded
by the
> kernel". The stuck ucom in turn prevents usb from getting unloaded and
the
> machine cannot poweroff.
> 
> I have already tried disabling EHCI, but it does not help. Any ideas on
either
> getting uhci to properly detach on shutdown or getting rid of ucom?
> 
> 
> Cheers,
> -- 
>    ,_,   | Michael Nottebrock               | lofi@freebsd.org
>  (/^ ^\) | FreeBSD - The Power to Serve     | http://www.freebsd.org
>    \u/   | K Desktop Environment on FreeBSD | http://freebsd.kde.org
> [2 This is a digitally signed message part. <application/pgp-signature
(7bit)>]
> 
Index: sys/dev/usb/ucom.c
==================================================================RCS file:
/home/ncvs/src/sys/dev/usb/ucom.c,v
retrieving revision 1.64
diff -u -r1.64 ucom.c
--- sys/dev/usb/ucom.c	25 Jun 2007 06:40:20 -0000	1.64
+++ sys/dev/usb/ucom.c	21 Jan 2008 12:54:00 -0000
@@ -1,7 +1,8 @@
 /*	$NetBSD: ucom.c,v 1.40 2001/11/13 06:24:54 lukem Exp $	*/
 
 /*-
- * Copyright (c) 2001-2003, 2005 Shunsuke Akiyama
<akiyama@jp.FreeBSD.org>.
+ * Copyright (c) 2001-2003, 2005, 2008
+ *	Shunsuke Akiyama <akiyama@jp.FreeBSD.org>.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -113,6 +114,7 @@
 #define DPRINTFN(n, x)
 #endif
 
+static int ucom_modevent(module_t, int, void *);
 static void ucom_cleanup(struct ucom_softc *);
 static int ucomparam(struct tty *, struct termios *);
 static void ucomstart(struct tty *);
@@ -135,7 +137,7 @@
 
 static moduledata_t ucom_mod = {
 	"ucom",
-	NULL,
+	ucom_modevent,
 	NULL
 };
 
@@ -143,6 +145,21 @@
 MODULE_DEPEND(ucom, usb, 1, 1, 1);
 MODULE_VERSION(ucom, UCOM_MODVER);
 
+static int
+ucom_modevent(module_t mod, int type, void *data)
+{
+	switch (type) {
+	case MOD_LOAD:
+		break;
+	case MOD_UNLOAD:
+		break;
+	default:
+		return (EOPNOTSUPP);
+		break;
+	}
+	return (0);
+}
+
 int
 ucom_attach(struct ucom_softc *sc)
 {

-- 
Shunsuke Akiyama
akiyama@jp.FreeBSD.org
akiyama@FreeBSD.org