From owner-p4-projects@FreeBSD.ORG  Wed Dec  5 19:10:44 2007
Return-Path: <owner-p4-projects@FreeBSD.ORG>
Delivered-To: p4-projects@freebsd.org
Received: by hub.freebsd.org (Postfix, from userid 32767)
	id 0355516A41B; Wed,  5 Dec 2007 19:10:44 +0000 (UTC)
Delivered-To: perforce@FreeBSD.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id A2E4216A417
	for <perforce@FreeBSD.org>; Wed,  5 Dec 2007 19:10:43 +0000 (UTC)
	(envelope-from hselasky@FreeBSD.org)
Received: from repoman.freebsd.org (repoman.freebsd.org
	[IPv6:2001:4f8:fff6::29])
	by mx1.freebsd.org (Postfix) with ESMTP id 954B213C45D
	for <perforce@FreeBSD.org>; Wed,  5 Dec 2007 19:10:43 +0000 (UTC)
	(envelope-from hselasky@FreeBSD.org)
Received: from repoman.freebsd.org (localhost [127.0.0.1])
	by repoman.freebsd.org (8.14.1/8.14.1) with ESMTP id lB5JAhDQ007240
	for <perforce@FreeBSD.org>; Wed, 5 Dec 2007 19:10:43 GMT
	(envelope-from hselasky@FreeBSD.org)
Received: (from perforce@localhost)
	by repoman.freebsd.org (8.14.1/8.14.1/Submit) id lB5JAhsB007237
	for perforce@freebsd.org; Wed, 5 Dec 2007 19:10:43 GMT
	(envelope-from hselasky@FreeBSD.org)
Date: Wed, 5 Dec 2007 19:10:43 GMT
Message-Id: <200712051910.lB5JAhsB007237@repoman.freebsd.org>
X-Authentication-Warning: repoman.freebsd.org: perforce set sender to
	hselasky@FreeBSD.org using -f
From: Hans Petter Selasky <hselasky@FreeBSD.org>
To: Perforce Change Reviews <perforce@FreeBSD.org>
Cc: 
Subject: PERFORCE change 130284 for review
X-BeenThere: p4-projects@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: p4 projects tree changes <p4-projects.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/p4-projects>,
	<mailto:p4-projects-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/p4-projects>
List-Post: <mailto:p4-projects@freebsd.org>
List-Help: <mailto:p4-projects-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/p4-projects>,
	<mailto:p4-projects-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Wed, 05 Dec 2007 19:10:44 -0000

http://perforce.freebsd.org/chv.cgi?CH=130284

Change 130284 by hselasky@hselasky_laptop001 on 2007/12/05 19:10:08

	
	Workaround for buggy USB devices that have no strings.

Affected files ...

.. //depot/projects/usb/src/sys/dev/usb/usb_subr.c#66 edit

Differences ...

==== //depot/projects/usb/src/sys/dev/usb/usb_subr.c#66 (text+ko) ====

@@ -1471,9 +1471,29 @@
 		udev->no_strings = 1;
 	}
 #endif
+
+	/*
+	 * Workaround for buggy USB devices.
+	 *
+	 * It appears that some string-less USB chips will crash and
+	 * disappear if any attempts are made to read any string
+	 * descriptors.
+	 *
+	 * Try to detect such chips by checking the strings in the USB
+	 * device descriptor. If no strings are present there we
+	 * simply disable all USB strings.
+	 */
+
+	if (udev->ddesc.iManufacturer ||
+	    udev->ddesc.iProduct ||
+	    udev->ddesc.iSerialNumber) {
 	/* setup language ID */
 	err = usbreq_get_string_desc(udev, &usb_global_lock, buf, 4,
 	    0, USB_LANGUAGE_TABLE);
+	} else {
+	  err = USBD_INVAL;
+	}
+
 	if (err || (buf[0] < 4)) {
 		udev->no_strings = 1;
 	} else {