From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Brownell Subject: Re: [PATCH] dm9601: handle corrupt mac address Date: Tue, 6 Jan 2009 02:28:16 -0800 Message-ID: <200901060228.16744.david-b@pacbell.net> References: <20090106061414.GA3677@localhost> <20090106082928.GB19690@localhost> <874p0cvnae.fsf@macbook.be.48ers.dk> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Wu Fengguang , netdev@vger.kernel.org To: Peter Korsgaard Return-path: Received: from smtp117.sbc.mail.sp1.yahoo.com ([69.147.64.90]:35276 "HELO smtp117.sbc.mail.sp1.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751191AbZAFK2T (ORCPT ); Tue, 6 Jan 2009 05:28:19 -0500 In-Reply-To: <874p0cvnae.fsf@macbook.be.48ers.dk> Content-Disposition: inline Sender: netdev-owner@vger.kernel.org List-ID: On Tuesday 06 January 2009, Peter Korsgaard wrote: > So what happens if you plug in 2 devices without an EEPROM? Do they > get the same MAC address? That seems broken. What happens when you unplug one then re-plug it? Maybe someone trips over the USB cable, or it gets an electrical glitch that evalutes to disconnect/reconnect... It gets the same address again. Not particularly broken. Note that Ethernet was *designed* around using a single address per host ... I still have XNS docs sitting around somewhere, that was a fairly significant thing. One of the original reasons Ethernet adapter addresses could change was to make sure that all Ethernet interfaces on a host would use the same address. That said ... if it bothers you, that's easy to change in userspace. This code has worked this way for around nine years now; I don't recall any previous complaints. - Dave