From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 7 May 2002 13:19:30 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 7 May 2002 13:19:29 -0400 Received: from mailhost.mipsys.com ([62.161.177.33]:35782 "EHLO mailhost.mipsys.com") by vger.kernel.org with ESMTP id ; Tue, 7 May 2002 13:19:28 -0400 From: To: Linus Torvalds , Alan Cox Cc: Padraig Brady , Anton Altaparmakov , Martin Dalecki , Kernel Mailing List Subject: Re: [PATCH] 2.5.14 IDE 56 Date: Tue, 7 May 2002 19:19:46 +0200 Message-Id: <20020507171946.29430@mailhost.mipsys.com> In-Reply-To: X-Mailer: CTM PowerMail 3.1.2 F MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > /driverfs/root/pci0/00:1f.4/usb_bus/000/ > >and it wouldn't be impossible (or even necessarily very hard) to make an >IDE controller export the "IDE device tree" the same way a USB controller >now exports the "USB device tree". > >For things like hotplug etc, I think driverfs is eventually the only way >to go, simply because it gives you the full (and unambiguous) path to >_any_ device, and is completely bus-agnostic. > >But there is definitely a potential backwards-compatibility-issue. One interesting thing here would be to have some optional link between the bus-oriented device tree and the function-oriented tree (ie. devfs or simply /dev). For example, an IDE node in driverfs could eventually hold symlinks to the entries it provides in /dev when using devfs (or just provide major/minor when not using devfs). What do you think ? One problem I've been faced with on ppc is to be able to match a linux device with what the firmware (Open Firmware) thinks that device is. The firmware view is bus-centered and it would be pretty easy to provide some additional entries in driverfs that give the OF fullpath of a given device. But then, the link between the actual driver in driverfs and the "device" as used by, for example, the filesystem isn't trivial. Ben.