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=-17.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE, SPF_PASS autolearn=unavailable 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 E9B47C07E9B for ; Wed, 21 Jul 2021 11:14:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CF33260FED for ; Wed, 21 Jul 2021 11:14:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235233AbhGUKdS (ORCPT ); Wed, 21 Jul 2021 06:33:18 -0400 Received: from mail.kernel.org ([198.145.29.99]:55646 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238301AbhGUJsh (ORCPT ); Wed, 21 Jul 2021 05:48:37 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 5063B6044F; Wed, 21 Jul 2021 10:29:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1626863353; bh=V7djkVVl929sbXP118vb28LnoFtni/31Vo8GPg09wsg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=FcUxNN89zmCPrGAKO0cORrnwJIx3mtxA0qyyCfDQ/+vhJ4gPWo8X6FVxJr3QU5BxR DMEW4HmYAFBSqbSlJP5ZZmTDnAa1SJPAifyj8uIvs+iHo1UU00B0/AOMU7951IyzGI Q3Yo8vNTgw6ZcmkDfQNCUnVvBKddbPzOqofb5M2Y= Date: Wed, 21 Jul 2021 12:29:11 +0200 From: Greg Kroah-Hartman To: Serge Semin Cc: Krzysztof Kozlowski , Rob Herring , Serge Semin , John Stultz , Felipe Balbi , Florian Fainelli , Andy Gross , Bjorn Andersson , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , linux-arm-msm , Linux USB List , lkml , linux-arm-kernel , Amit Pundir Subject: Re: [PATCH 29/29] arm64: dts: qcom: Harmonize DWC USB3 DT nodes name Message-ID: References: <20201020115959.2658-1-Sergey.Semin@baikalelectronics.ru> <20201020115959.2658-30-Sergey.Semin@baikalelectronics.ru> <20210714124807.o22mottsrg3tv6nt@mobilestation> <20210721100220.ddfxwugivsndsedv@mobilestation> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210721100220.ddfxwugivsndsedv@mobilestation> Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On Wed, Jul 21, 2021 at 01:02:20PM +0300, Serge Semin wrote: > Hi Greg, > @Krzysztof, @Rob, please join the discussion so to finally get done > with the concerned issue. > > On Wed, Jul 21, 2021 at 09:38:54AM +0200, Greg Kroah-Hartman wrote: > > On Wed, Jul 14, 2021 at 03:48:07PM +0300, Serge Semin wrote: > > > Hello John, > > > > > > On Tue, Jul 13, 2021 at 05:07:00PM -0700, John Stultz wrote: > > > > On Tue, Oct 20, 2020 at 5:10 AM Serge Semin > > > > wrote: > > > > > > > > > > In accordance with the DWC USB3 bindings the corresponding node > > > > > name is suppose to comply with the Generic USB HCD DT schema, which > > > > > requires the USB nodes to have the name acceptable by the regexp: > > > > > "^usb(@.*)?" . Make sure the "snps,dwc3"-compatible nodes are correctly > > > > > named. > > > > > > > > > > Signed-off-by: Serge Semin > > > > > > > > > > > I know folks like to ignore this, but this patch breaks AOSP on db845c. :( > > > > > > Sorry to hear that. Alas there is no much can be done about it. > > > > Yes there is, we can revert the change. We do not break existing > > configurations, sorry. > > By reverting this patch we'll get back to the broken dt-bindings > since it won't comply to the current USB DT-nodes requirements > which at this state well describe the latest DT spec: > https://github.com/devicetree-org/devicetree-specification/releases/tag/v0.3 > Thus the dtbs_check will fail for these nodes. > > Originally this whole patchset was connected with finally getting the > DT-node names in order to comply with the standard requirement and it > was successful mostly except a few patches which still haven't been > merged in. > > Anyway @Krzysztof has already responded to the complain regarding this > issue here: > https://lore.kernel.org/lkml/20201221210423.GA2504@kozik-lap/ > but noone cared to respond on his reasonable questions in order to > get to a suitable solution for everyone. Instead we are > getting another email with the same request to revert the changes. > Here is the quote from the Krzysztof email so we could continue the > discussion: > > On Mon, 21 Dec 2020 13:04:27 -0800 (PST), Krzysztof Kozlowski wrote: > > On Mon, Dec 21, 2020 at 12:24:11PM -0800, John Stultz wrote: > > > On Sat, Dec 19, 2020 at 3:06 AM Krzysztof Kozlowski wrote: > > > > ... > > > > > > > > The node names are not part of an ABI, are they? I expect only > > > > compatibles and properties to be stable. If user-space looks for > > > > something by name, it's a user-space's mistake. Not mentioning that you > > > > also look for specific address... Imagine remapping of addresses with > > > > ranges (for whatever reason) - AOSP also would be broken? Addresses are > > > > definitely not an ABI. > > > > > > Though that is how it's exported through sysfs. > > > > The ABI is the format of sysfs file for example in /sys/devices. However > > the ABI is not the exact address or node name of each device. > > > > > In AOSP it is then used to setup the configfs gadget by writing that > > > value into /config/usb_gadget/g1/UDC. > > > > > > Given there may be multiple controllers on a device, or even if its > > > just one and the dummy hcd driver is enabled, I'm not sure how folks > > > reference the "right" one without the node name? > > > > I think it is the same type of problem as for all other subsystems, e.g. > > mmc, hwmon/iio. They usually solve it either with aliases or with > > special property with the name/label. > > > > > I understand the fuzziness with sysfs ABI, and I get that having > > > consistent naming is important, but like the eth0 -> enp3s0 changes, > > > it seems like this is going to break things. > > > > One could argue whether interface name is or is not ABI. But please tell > > me how the address of a device in one's representation (for example DT) > > is a part of a stable interface? > > > > > Greg? Is there some better way AOSP should be doing this? > > > > If you need to find specific device, maybe go through the given bus and > > check compatibles? > > > > Best regards, > > Krzysztof > > So the main question is how is the DT-node really connected with ABI > and is supposed to be stable in that concern? > > As I see it even if it affects the configfs node name, then we may > either need to break that connection and somehow deliver DT-node-name > independent interface to the user-space or we have no choice but to > export the node with an updated name and ask of user-space to deal > with it. In both suggested cases the DT-node name will still conform > to the USB-node name DT spec. Currently we are at the second one. I really do not care what you all decide on, but you CAN NOT break existing working systems, sorry. That is why I have reverted this change in my tree and will send it to Linus soon. thanks, greg k-h