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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 14751C4338F for ; Wed, 11 Aug 2021 14:36:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DC98660FC0 for ; Wed, 11 Aug 2021 14:36:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232438AbhHKOgo (ORCPT ); Wed, 11 Aug 2021 10:36:44 -0400 Received: from vps0.lunn.ch ([185.16.172.187]:45174 "EHLO vps0.lunn.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232391AbhHKOgm (ORCPT ); Wed, 11 Aug 2021 10:36:42 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lunn.ch; s=20171124; h=In-Reply-To:Content-Disposition:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:From:Sender:Reply-To:Subject: Date:Message-ID:To:Cc:MIME-Version:Content-Type:Content-Transfer-Encoding: Content-ID:Content-Description:Content-Disposition:In-Reply-To:References; bh=u+OGBpgzBa8FBV8wLzAf0DvFVw5JlMQMj64MVlsCkcs=; b=JtrpVpuavK94hz2O2VRPzaFCu9 gJQU9eVkONWNNpUkPYtpJ65dWbI1guhYmQnXBnDkIlced7XELPkxJX12Hi0PSzL8SXicavi/oWaKC D1DqR7LDVaD07Zx1wHkI7ocTbBxQ8EVWUuUE+jZRMcAKQvQDuPLz1shhJ0ANN1TT3mFw=; Received: from andrew by vps0.lunn.ch with local (Exim 4.94.2) (envelope-from ) id 1mDpL3-00H87k-Mh; Wed, 11 Aug 2021 16:36:13 +0200 Date: Wed, 11 Aug 2021 16:36:13 +0200 From: Andrew Lunn To: Jakub Kicinski Cc: Ido Schimmel , "Keller, Jacob E" , netdev@vger.kernel.org, davem@davemloft.net, mkubecek@suse.cz, pali@kernel.org, vadimp@nvidia.com, mlxsw@nvidia.com, Ido Schimmel Subject: Re: [RFC PATCH net-next 1/8] ethtool: Add ability to control transceiver modules' low power mode Message-ID: References: <20210809102152.719961-1-idosch@idosch.org> <20210809102152.719961-2-idosch@idosch.org> <20210810065954.68036568@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> <20210810150544.3fec5086@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> <20210811060343.014724e8@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210811060343.014724e8@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Wed, Aug 11, 2021 at 06:03:43AM -0700, Jakub Kicinski wrote: > On Wed, 11 Aug 2021 14:33:06 +0300 Ido Schimmel wrote: > > # ethtool --set-module swp13 low-power on > > > > $ ethtool --show-module swp13 > > Module parameters for swp13: > > low-power true > > > > # ip link set dev swp13 up > > > > $ ip link show dev swp13 > > 127: swp13: mtu 1500 qdisc fq_codel state DOWN mode DEFAULT group default qlen 1000 > > link/ether 1c:34:da:18:55:49 brd ff:ff:ff:ff:ff:ff > > > > $ ip link show dev swp14 > > 128: swp14: mtu 1500 qdisc fq_codel state DOWN mode DEFAULT group default qlen 1000 > > link/ether 1c:34:da:18:55:4d brd ff:ff:ff:ff:ff:ff > > Oh, so if we set low-power true the carrier will never show up? > I thought Andrew suggested the setting is only taken into account > when netdev is down. Yes, that was my intention. If this low power mode also applies when the interface is admin up, it sounds like a foot gun. ip link show gives you no idea why the carrier is down, and people will assume the cable or peer is broken. We at least need a new flag, LOWER_DISABLED or similar to give the poor user some chance to figure out what is going on. To me, this setting should only apply when the link is admin down. Andrew