From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E58ABC433DB for ; Fri, 15 Jan 2021 19:26:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B233E23A5E for ; Fri, 15 Jan 2021 19:26:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732237AbhAOT07 (ORCPT ); Fri, 15 Jan 2021 14:26:59 -0500 Received: from mail.kernel.org ([198.145.29.99]:34180 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727049AbhAOT06 (ORCPT ); Fri, 15 Jan 2021 14:26:58 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 03701235F8; Fri, 15 Jan 2021 19:26:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1610738778; bh=H5G8eGoBoAb87BIVNQjIxm7imUUOeFnLnGVrmVtyAdQ=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=NP8k+Xt+KslGyCVm+KjP8tZ+YRSFojorkgTFAptqTiDfmlV4ZNJ6+MQRVN8TzPuQt +U1ksiyyDtRvJtAbrn/9PWi5SyATLJ9or/fm00tGurrq+zE5uHWTGtnNfHFyK3Y8L1 YAxLH8+A4dblscFCqxwwYh90WBWVagNcivlW8I3m7YyZhVUFGaP1DN8j0Oo31JYW5J 26Yc9OOwLzTeDFrT2uETMkwX+9Dq1lcCnPrlbbGgCNKjY/gWCRrumdDhlSzN/WLyYt VscIpPgLwvxRReLw67p77SrS+j0TfwfuYbm19e5QsyMDET8GBPITvcq0MpK0XgtdlU hu5slZlulCOog== Date: Fri, 15 Jan 2021 11:26:17 -0800 From: Jakub Kicinski To: Jiri Pirko Cc: netdev@vger.kernel.org, davem@davemloft.net, jacob.e.keller@intel.com, roopa@nvidia.com, mlxsw@nvidia.com Subject: Re: [patch net-next RFC 00/10] introduce line card support for modular switch Message-ID: <20210115112617.064deda8@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> In-Reply-To: <20210115143906.GM3565223@nanopsycho.orion> References: <20210113121222.733517-1-jiri@resnulli.us> <20210113182716.2b2aa8fa@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> <20210114074804.GK3565223@nanopsycho.orion> <20210114153013.2ce357b0@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> <20210115143906.GM3565223@nanopsycho.orion> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Fri, 15 Jan 2021 15:39:06 +0100 Jiri Pirko wrote: > >I'm not a SFP experts so maybe someone will correct me but AFAIU > >the QSFP (for optics) is the same regardless of breakout. It's the > >passive optical strands that are either bundled or not. So there is > >no way for the system to detect the cable type (AFAIK). > > For SFP module, you are able to detect those. Not sure you understand what I'm saying. Maybe you're thinking about DACs? This is a optical cable for breakout: https://www.fs.com/products/68048.html There is no electronics in it to "detect" things AFAIU. Same QSFP can be used with this cable or a non-breakout. > >Or to put it differently IMO the netdev should be provisioned if the > >system has a port into which user can plug in a cable. When there is > > Not really. For slit cables, the ports are provisioned not matter which > cable is connected, slitter 1->2/1->4 or 1->1 cable. > > > >a line card-sized hole in the chassis, I'd be surprised to see ports. > > > >That said I never worked with real world routers so maybe that's what > >they do. Maybe some with a Cisco router in the basement can tell us? :) > > The need for provision/pre-configure splitter/linecard is that the > ports/netdevices do not disapper/reappear when you replace > splitter/linecard. Consider a faulty linecard with one port burned. You > just want to replace it with new one. And in that case, you really don't > want kernel to remove netdevices and possibly mess up routing for > example. Having a single burned port sounds like a relatively rare scenario. Reconfiguring routing is not the end of the world. > >If the device really needs this configuration / can't detect things > >automatically, then we gotta do something like what you have. > >The only question is do we still want to call it a line card. > >Sounds more like a front panel module. At Netronome we called > >those phymods. > > Sure, the name is up to the discussion. We call it "linecard" > internally. I don't care about the name. Yeah, let's call it something more appropriate to indicate its breakout/retimer/gearbox nature, and we'll be good :)