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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B6D6BC25B08 for ; Sat, 20 Aug 2022 12:31:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345110AbiHTMb4 (ORCPT ); Sat, 20 Aug 2022 08:31:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59916 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344848AbiHTMbz (ORCPT ); Sat, 20 Aug 2022 08:31:55 -0400 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 05DCB6BCCA for ; Sat, 20 Aug 2022 05:31:55 -0700 (PDT) Received: from ptx.hi.pengutronix.de ([2001:67c:670:100:1d::c0]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1oPNdn-0005aE-Mi; Sat, 20 Aug 2022 14:31:51 +0200 Received: from ore by ptx.hi.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1oPNdk-0002pe-TW; Sat, 20 Aug 2022 14:31:48 +0200 Date: Sat, 20 Aug 2022 14:31:48 +0200 From: Oleksij Rempel To: Andrew Lunn Cc: devicetree@vger.kernel.org, kernel@pengutronix.de, Jonathan Corbet , netdev@vger.kernel.org, linux-doc@vger.kernel.org, Russell King , linux-kernel@vger.kernel.org, Eric Dumazet , Rob Herring , Krzysztof Kozlowski , David Jander , Jakub Kicinski , Paolo Abeni , "David S. Miller" , Heiner Kallweit , Luka Perkov , Robert Marko Subject: Re: [PATCH net-next v1 7/7] ethtool: add interface to interact with Ethernet Power Equipment Message-ID: <20220820123148.GH10138@pengutronix.de> References: <20220819120109.3857571-1-o.rempel@pengutronix.de> <20220819120109.3857571-8-o.rempel@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: X-Sent-From: Pengutronix Hildesheim X-URL: http://www.pengutronix.de/ X-Accept-Language: de,en X-Accept-Content-Type: text/plain User-Agent: Mutt/1.10.1 (2018-07-13) X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c0 X-SA-Exim-Mail-From: ore@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: devicetree@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Fri, Aug 19, 2022 at 11:15:09PM +0200, Andrew Lunn wrote: > > $ ip l > > ... > > 5: t1l1@eth0: .. > > ... > > > > $ ethtool --show-pse t1l1 > > PSE attributs for t1l1: > > PoDL PSE Admin State: disabled > > PoDL PSE Power Detection Status: disabled > > > > $ ethtool --set-pse t1l1 podl-pse-admin-control enable > > $ ethtool --show-pse t1l1 > > PSE attributs for t1l1: > > PoDL PSE Admin State: enabled > > PoDL PSE Power Detection Status: delivering power > > Here you seem to indicate that delivering power is totally independent > of the interface admin status, . The interface is > admin down, yet you can make it deliver power. I thought there might > be a link between interface admin status and power? Do the standards > say anything about this? Is there some sort of industrial norm? > > I'm also wondering about the defaults. It seems like the defaults you > are proposing is power is off by default, and you have to use ethtool > to enable power. That does not seem like the most friendly > settings. Why not an 'auto' mode where if the PHY has PoDL PSE > capabilities, on ifup it is enabled, on ifdown it is disabled? And you > can put it into a 'manual' mode where you control it independent of > administrative status of the interface? Hm. I would say, safe option is to enable PSE manually. Here are my reasons: - some system may require to have power be enabled on boot, before we start to care about administrative state of the interface. - in some cases powered device should stay enabled, even if we do ifup/ifdown I assume, safe defaults should be: - keep PSE always off, except system was configured to enable it on boot. - keep PSE on after it was enabled, even on if up/down - bind PSE admin state to the interface state only if user explicitly requested it. At this round is only default, manual mode is implemented. Automatic mode can be added later if needed. These are my points, but i'm open for discussion. Regards, Oleksij -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |