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=-5.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 54123C433E3 for ; Mon, 27 Jul 2020 17:21:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3FEDA207FC for ; Mon, 27 Jul 2020 17:21:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730424AbgG0RVm (ORCPT ); Mon, 27 Jul 2020 13:21:42 -0400 Received: from foss.arm.com ([217.140.110.172]:48270 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726617AbgG0RVm (ORCPT ); Mon, 27 Jul 2020 13:21:42 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 89E6A30E; Mon, 27 Jul 2020 10:21:41 -0700 (PDT) Received: from bogus (unknown [10.37.12.41]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id F27E73F718; Mon, 27 Jul 2020 10:21:38 -0700 (PDT) Date: Mon, 27 Jul 2020 18:21:36 +0100 From: Sudeep Holla To: Andrew Lunn Cc: Jeremy Linton , Calvin Johnson , Russell King - ARM Linux admin , Jon , Cristi Sovaiala , Ioana Ciornei , Andy Shevchenko , Florian Fainelli , Madalin Bucur , netdev@vger.kernel.org, Sudeep Holla , linux.cj@gmail.com, linux-acpi@vger.kernel.org Subject: Re: [net-next PATCH v7 1/6] Documentation: ACPI: DSD: Document MDIO PHY Message-ID: <20200727172136.GC8003@bogus> References: <20200715090400.4733-1-calvin.johnson@oss.nxp.com> <20200715090400.4733-2-calvin.johnson@oss.nxp.com> <1a031e62-1e87-fdc1-b672-e3ccf3530fda@arm.com> <20200724133931.GF1472201@lunn.ch> <97973095-5458-8ac2-890c-667f4ea6cd0e@arm.com> <20200724191436.GH1594328@lunn.ch> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200724191436.GH1594328@lunn.ch> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Fri, Jul 24, 2020 at 09:14:36PM +0200, Andrew Lunn wrote: > > Hence my previous comment that we should consider this an escape > > hatch rather than the last word in how to describe networking on > > ACPI/SBSA platforms. > > One problem i have is that this patch set suggests ACPI can be used to > describe complex network hardware. It is opening the door for others > to follow and add more ACPI support in networking. How long before it > is not considered an escape hatch, but the front door? > I understand your concerns here. But as I mentioned in other email in the same thread, it is very tricky problem to solve as no one is ready to take up and maintain these. > For an example, see > > https://patchwork.ozlabs.org/project/netdev/patch/1595417547-18957-3-git-send-email-vikas.singh@puresoftware.com/ > > It is hard to see what the big picture is here. The [0/2] patch is not > particularly good. But it makes it clear that people are wanting to > add fixed-link PHYs into ACPI. These are pseudo devices, used to make > the MAC think it is connected to a PHY when it is not. The MAC still > gets informed of link speed, etc via the standard PHYLIB API. They are > mostly used for when the Ethernet MAC is directly connected to an > Ethernet Switch, at a MAC to MAC level. > > Now i could be wrong, but are Ethernet switches something you expect > to see on ACPI/SBSA platforms? Or is this a legitimate use of the > escape hatch? > My guess is that similar products running on other architectures(namely x86) might be running ACPI and hence the push to have ACPI on such ARM systems. It may weak argument for that and I agree with it. I want to think it as legitimate use here but I am well aware and afraid that this may become front door instead of escape hatch. Sorry, I am not helpful at all, but I am just sharing my personal opinion on this matter. -- Regards, Sudeep