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 54FAAC4338F for ; Wed, 18 Aug 2021 22:55:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2F7096108E for ; Wed, 18 Aug 2021 22:55:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233928AbhHRW4X (ORCPT ); Wed, 18 Aug 2021 18:56:23 -0400 Received: from vps0.lunn.ch ([185.16.172.187]:57460 "EHLO vps0.lunn.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229478AbhHRW4W (ORCPT ); Wed, 18 Aug 2021 18:56:22 -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=6fgndGUwPDLOoHHMWBat09B116X4cJTIkzdn9KacSgk=; b=L/c7d5a5YCJHNI0YTq19osSBPG oUgfe/S3SvqgSaoYFMK/JFq4PfaInxuokDazLytAkRIUIrI8lw1P95QXlhNu37kuHnqjx6/w1MgAo hMunARwDx+KGrwQ+rZGL/fGUKsEW+r7ylvcbLX7ISmfK+UvJsRqe2Cgpv98Btk5nfiYM=; Received: from andrew by vps0.lunn.ch with local (Exim 4.94.2) (envelope-from ) id 1mGUTH-000rpJ-RW; Thu, 19 Aug 2021 00:55:43 +0200 Date: Thu, 19 Aug 2021 00:55:43 +0200 From: Andrew Lunn To: Jakub Kicinski Cc: Ido Schimmel , netdev@vger.kernel.org, davem@davemloft.net, mkubecek@suse.cz, pali@kernel.org, jacob.e.keller@intel.com, jiri@nvidia.com, vadimp@nvidia.com, mlxsw@nvidia.com, Ido Schimmel Subject: Re: [RFC PATCH net-next v2 1/6] ethtool: Add ability to control transceiver modules' power mode Message-ID: References: <20210818155202.1278177-1-idosch@idosch.org> <20210818155202.1278177-2-idosch@idosch.org> <20210818153241.7438e611@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210818153241.7438e611@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Wed, Aug 18, 2021 at 03:32:41PM -0700, Jakub Kicinski wrote: > On Wed, 18 Aug 2021 18:51:57 +0300 Ido Schimmel wrote: > > +MODULE_SET > > +========== > > + > > +Sets transceiver module parameters. > > + > > +Request contents: > > + > > + ====================================== ====== ========================== > > + ``ETHTOOL_A_MODULE_HEADER`` nested request header > > + ``ETHTOOL_A_MODULE_POWER_MODE_POLICY`` u8 power mode policy > > + ====================================== ====== ========================== > > + > > +When set, the optional ``ETHTOOL_A_MODULE_POWER_MODE_POLICY`` attribute is used > > +to set the transceiver module power policy enforced by the host. Possible > > +values are: > > + > > +.. kernel-doc:: include/uapi/linux/ethtool.h > > + :identifiers: ethtool_module_power_mode_policy > > + > > +For SFF-8636 modules, low power mode is forced by the host according to table > > +6-10 in revision 2.10a of the specification. > > + > > +For CMIS modules, low power mode is forced by the host according to table 6-12 > > +in revision 5.0 of the specification. > > + > > +To avoid changes to the operational state of the device, power mode policy can > > +only be set when the device is administratively down. > > Would you mind explaining why? Part of the issue is we have two different sorts of policy mixed together. ETHTOOL_MODULE_POWER_MODE_POLICY_LOW and ETHTOOL_MODULE_POWER_MODE_POLICY_HIGH change the state now. This could be a surprise to a user when there link disappears for the ETHTOOL_MODULE_POWER_MODE_POLICY_LOW case, when the interface is admin up. ETHTOOL_MODULE_POWER_MODE_POLICY_HIGH_ON_UP however follows the state of the interface. So there should not be any surprises. I actually think ETHTOOL_MODULE_POWER_MODE_POLICY_HIGH_ON_UP should be allowed at any time, just to make it easier to use. > > +/** > > + * enum ethtool_module_power_mode_policy - plug-in module power mode policy > > + * @ETHTOOL_MODULE_POWER_MODE_POLICY_LOW: Module is always in low power mode. > > Did you have a use case for this one or is it for completeness? Seems > like user can just bring the port down if they want no carrier? My > understanding was you primarily wanted the latter two, and those can > be freely changed when netdev is running, right? > > > + * @ETHTOOL_MODULE_POWER_MODE_POLICY_HIGH: Module is always in high power mode. > > + * @ETHTOOL_MODULE_POWER_MODE_POLICY_HIGH_ON_UP: Module is transitioned by the > > + * host to high power mode when the first port using it is put > > + * administratively up and to low power mode when the last port using it > > + * is put administratively down. > > s/HIGH_ON_UP/AUTO/ ? > high on up == low on down, right, seems arbitrary to pick one over the > other Should we also document what the default is? Seems like ETHTOOL_MODULE_POWER_MODE_POLICY_HIGH_ON_UP is the generic network interface default, so maybe it should also be the default for SFPs? Andrew