From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roopa Prabhu Subject: Re: [PATCH net-next v2 0/3] ethtool: support for forward error correction mode setting on a link Date: Fri, 6 Oct 2017 10:05:27 -0700 Message-ID: References: <1501199248-24695-1-git-send-email-roopa@cumulusnetworks.com> <20170727193320.308e86c3@cakuba.netronome.com> <20170728094620.525ba156@cakuba.netronome.com> <20171005113055.477aec34@cakuba.netronome.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Cc: "davem@davemloft.net" , "John W. Linville" , "netdev@vger.kernel.org" , Vidya Sagar Ravipati , Dustin Byford , Dave Olson , Casey Leedom , Gal Pressman , Andrew Lunn , Manoj Malviya , Santosh Rastapur , yuval.mintz@qlogic.com, odedw@mellanox.com, Ariel Almog , Jeff Kirsher , Dirk van der Merwe To: Jakub Kicinski Return-path: Received: from mail-ua0-f169.google.com ([209.85.217.169]:51567 "EHLO mail-ua0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751491AbdJFRF3 (ORCPT ); Fri, 6 Oct 2017 13:05:29 -0400 Received: by mail-ua0-f169.google.com with SMTP id 47so11129673uas.8 for ; Fri, 06 Oct 2017 10:05:28 -0700 (PDT) In-Reply-To: <20171005113055.477aec34@cakuba.netronome.com> Sender: netdev-owner@vger.kernel.org List-ID: On Thu, Oct 5, 2017 at 11:30 AM, Jakub Kicinski wrote: > On Fri, 28 Jul 2017 23:28:26 -0700, Roopa Prabhu wrote: >> On Fri, Jul 28, 2017 at 9:46 AM, Jakub Kicinski wrote: >> > On Fri, 28 Jul 2017 07:53:01 -0700, Roopa Prabhu wrote: >> >> On Thu, Jul 27, 2017 at 7:33 PM, Jakub Kicinski wrote: >> >> > On Thu, 27 Jul 2017 16:47:25 -0700, Roopa Prabhu wrote: >> >> >> From: Roopa Prabhu >> >> >> >> >> >> Forward Error Correction (FEC) modes i.e Base-R >> >> >> and Reed-Solomon modes are introduced in 25G/40G/100G standards >> >> >> for providing good BER at high speeds. Various networking devices >> >> >> which support 25G/40G/100G provides ability to manage supported FEC >> >> >> modes and the lack of FEC encoding control and reporting today is a >> >> >> source for interoperability issues for many vendors. >> >> >> FEC capability as well as specific FEC mode i.e. Base-R >> >> >> or RS modes can be requested or advertised through bits D44:47 of base link >> >> >> codeword. >> >> >> >> >> >> This patch set intends to provide option under ethtool to manage and >> >> >> report FEC encoding settings for networking devices as per IEEE 802.3 >> >> >> bj, bm and by specs. >> >> >> >> >> >> v2 : >> >> >> - minor patch format fixes and typos pointed out by Andrew >> >> >> - there was a pending discussion on the use of 'auto' vs >> >> >> 'automatic' for fec settings. I have left it as 'auto' >> >> >> because in most cases today auto is used in place of >> >> >> automatic to represent automatically generated values. >> >> >> We use it in other networking config too. I would prefer >> >> >> leaving it as auto. >> >> > >> >> > On the subject of resetting the values when module is replugged I >> >> > assume what was previously described remains: >> >> > - we always allow users to set the FEC regardless of the module type; >> >> > - if user set an incorrect FEC for the module type (or module gets >> >> > swapped) the link will be administratively taken down by either >> >> > the driver or FW. >> >> > >> >> > Is that correct? Am I misremembering? >> >> >> >> yes, correct. And possible future sfp hotplug events can give user-space >> >> more info to react to module type changes etc. >> > >> > OK, if nobody else objects and we go with that - lets make sure we >> > document clearly those are expected :) My concern is that if there is >> > ever 10G + RS FEC standard we don't want to end up in a situation where >> > some drivers silently ignore FEC settings in 10G and other apply it. >> > So let's make it clear what the intended Linux behaviour is. It could >> > be in the ethtool man page, or the kernel somewhere. >> >> sure :), ack. We will document it in the ethtool manpage. > > Hi Roopa! Did you ever publish the ethtool user space patches at all? > I can't find them... not yet, they are in my queue. will submit in the next two days.