From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752799Ab2DUF5f (ORCPT ); Sat, 21 Apr 2012 01:57:35 -0400 Received: from mail-pz0-f52.google.com ([209.85.210.52]:59036 "EHLO mail-pz0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751425Ab2DUF5d (ORCPT ); Sat, 21 Apr 2012 01:57:33 -0400 Date: Sat, 21 Apr 2012 13:56:59 +0800 From: Wang YanQing To: Alan Stern Cc: Greg KH , lkml , linux-usb@vger.kernel.org Subject: Re: [RFC]Is usb port number fixed? Message-ID: <20120421055658.GA5277@udknight> Mail-Followup-To: Wang YanQing , Alan Stern , Greg KH , lkml , linux-usb@vger.kernel.org References: <20120420153727.GA29331@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Apr 20, 2012 at 08:32:37PM -0400, Alan Stern wrote: > In this particular case, it is guaranteed that the left USB port will > always be numbered as X-1.1:1.0 and the right port as X-1.2:1.0, where > the number X may change from one boot to another. But the -1.1:1.0 and > -1.2:1.0 parts will always be the same. > > This is because X is the bus number, which is allowed to change. The > -1.1:1.0 and -1.2:1.0 values are port, configuration, and interface > numbers. They will never change, because they come from the hardware. Yes, configuration and interface come from the hardware, but I don't know where the port come from, at least I don't think the port comes from the same hardware with the configuration and interface, do you mean port come from the hub?