From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: Ethernet MAC address question Date: Tue, 15 Jun 2004 12:11:18 -0400 Sender: netdev-bounce@oss.sgi.com Message-ID: <40CF1FA6.3020701@pobox.com> References: <200406151538.i5FFcJ720553@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Cc: Mark Brown , netdev@oss.sgi.com Return-path: To: Don Fry In-Reply-To: <200406151538.i5FFcJ720553@localhost.localdomain> Errors-to: netdev-bounce@oss.sgi.com List-Id: netdev.vger.kernel.org Don Fry wrote: > So how does the driver distinguish between a valid, but incorrect MAC > address, and the 'correct' MAC address? The incorrect one that is the > value that just happened to be in the uninitialized volatile registers, > and the correct address which some magic platform means loaded into the > same, but this time initialized, volatile registers. You have to notice that certain platform-specific attributes are present, that tells your code to search in rather than the standard place for MAC address. For example, some Compaqs have a magic MAC address location (this might even be pcnet32), and one solution proposed was looking for the platform's DMI table identifiers. Another solution -- working -- was to load the MAC address registers when the driver loads, and just hope it is a correct address. Jeff