From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261727AbVASPyF (ORCPT ); Wed, 19 Jan 2005 10:54:05 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261764AbVASPyF (ORCPT ); Wed, 19 Jan 2005 10:54:05 -0500 Received: from mail1.kontent.de ([81.88.34.36]:14282 "EHLO Mail1.KONTENT.De") by vger.kernel.org with ESMTP id S261727AbVASPyB (ORCPT ); Wed, 19 Jan 2005 10:54:01 -0500 From: Oliver Neukum To: Pete Zaitcev Subject: Re: usbmon, usb core, ARM Date: Wed, 19 Jan 2005 16:54:07 +0100 User-Agent: KMail/1.7.1 Cc: David Brownell , linux-kernel@vger.kernel.org, greg@kroah.com, linux-usb-devel@lists.sourceforge.net References: <20050118212033.26e1b6f0@localhost.localdomain> <200501182214.25273.david-b@pacbell.net> <20050119074208.3bfa6458@localhost.localdomain> In-Reply-To: <20050119074208.3bfa6458@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-2" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200501191654.07619.oliver@neukum.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Am Mittwoch, 19. Januar 2005 16:42 schrieb Pete Zaitcev: > On Tue, 18 Jan 2005 22:14:24 -0800, David Brownell wrote: > > > > > Also, I don't like the idea of scattering knowledge all over the place > > > > that the root hub is always given address 1 ... > > > > which you didn't address yet. > > Yes, I have to look why you do not like using the pipe. Relying on pipe makes > tests dependant on URB only. No references to bus or HCD, therefore no > extra refcounts or worries about oopses. Also, HC drivers zero out the > urb->dev in giveback sequence which is a royal pain when trying to identify > a root hub. I thought about adding an extra flag like URB_ROOT_HUB to split That idea was good. It is simple and will simplify the code cleanly. > this use from the abuse of URB_NO_TRANSFER_DMA_MAP, but pipe looks better > all around. If you look at it from the angle I did, it stands to reason > that excessive encapsulation only masks _why_ it was safer, e.g. if one sees > something like urb_is_root_hub(urb), one must look up the implementation > to know if it uses urb->dev or not. Relying on address 1 without any symbolic > constant is obviously a bad idea though, I'll fix that. True, but pipe must die. It has no real basis. Regards Oliver