From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [RFC] [PATCH] ethtool: Flags for fibre speed switching Date: Tue, 22 Jun 2010 10:17:44 -0700 (PDT) Message-ID: <20100622.101744.70185793.davem@davemloft.net> References: <1276543562.2074.41.camel@achroite.uk.solarflarecom.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, jgarzik@redhat.com, linux-net-drivers@solarflare.com To: bhutchings@solarflare.com Return-path: Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:42641 "EHLO sunset.davemloft.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755423Ab0FVRRc (ORCPT ); Tue, 22 Jun 2010 13:17:32 -0400 In-Reply-To: <1276543562.2074.41.camel@achroite.uk.solarflarecom.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Ben Hutchings Date: Mon, 14 Jun 2010 20:26:02 +0100 > ethtool.h currently defines only SUPPORTED_FIBRE to cover all fibre > modes. However, SFP+ slots support both 1G and 10G fibre modules and > some modules are dual-speed. Some drivers use the BASE-T flags for SFP+ > modules of all media types, but this is strictly incorrect and can be > confusing as there are real BASE-T modules for SFP+. There should be > distinct flags for fibre modes. However I'm not sure whether it's worth > defining flags for each fibre mode (there are quite a few) or only for > each speed. > > Similarly there is only ADVERTISED_FIBRE to cover all fibre modes. > Although there is no AN protocol for fibre, an SFP+ NIC effectively > autonegotiates its speed with the module. By default, an SFP+ NIC will > accept both 1G and 10G modules and switch speed automatically. With a > dual-speed module, the NIC driver can allow forcing the speed through > ethtool, but unless it maintains some hidden state it must reset the > speed whenever the module is hotplugged (perhaps accidentally). So it > should be possible for the administrator to control speed selection in a > sticky way through the advertising mask. I'm fine with this, feel free to make a formal submission for net-next-2.6