Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756284AbYH0S6U (ORCPT ); Wed, 27 Aug 2008 14:58:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752426AbYH0S6K (ORCPT ); Wed, 27 Aug 2008 14:58:10 -0400 Received: from iolanthe.rowland.org ([192.131.102.54]:32983 "HELO iolanthe.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1752248AbYH0S6J (ORCPT ); Wed, 27 Aug 2008 14:58:09 -0400 Date: Wed, 27 Aug 2008 14:58:08 -0400 (EDT) From: Alan Stern X-X-Sender: stern@iolanthe.rowland.org To: Greg KH , Oliver Neukum cc: USB list , Stefan Kopp , Marcel Janssen , Felipe Balbi , Kernel development list Subject: Re: [PATCH] USB: add USB test and measurement class driver - round 2 In-Reply-To: <20080827183615.GA15692@kroah.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1407 Lines: 39 On Wed, 27 Aug 2008, Greg KH wrote: > On Wed, Aug 27, 2008 at 02:28:22PM -0400, Alan Stern wrote: > > On Wed, 27 Aug 2008, Greg KH wrote: > > > > > Here's an updated version of the usbtmc driver, with all of the > > > different issues that have been raised, hopefully addressed. > > > > This is an example of what I was discussing with Oliver. In all > > likelihood you simply don't need usbtmc_mutex, and using it will cause > > a lockdep violation. > > > > That's why so many of the other USB class drivers don't have an > > analogous static mutex. > > Ok, then it's just safe to drop this static mutex entirely, right? Yes, once you add the call to usb_deregister_dev. On Wed, 27 Aug 2008, Oliver Neukum wrote: > And this rule depends on sharing the USB major or not. This needs > a big fat mention in Documentation. You mean that the open/disconnect locking rule applies only to drivers that call usb_register_dev, i.e, drivers using the USB major. Right? I agree that it deserves to be mentioned in the documentation somewhere. Where would be a good place? None of the existing files in Documentation/usb seem appropriate. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/