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=-3.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 79013C43463 for ; Fri, 18 Sep 2020 15:01:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2A1502075E for ; Fri, 18 Sep 2020 15:01:19 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="HVomqNkH" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726806AbgIRPBP (ORCPT ); Fri, 18 Sep 2020 11:01:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60934 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725955AbgIRPBP (ORCPT ); Fri, 18 Sep 2020 11:01:15 -0400 Received: from mail-io1-xd44.google.com (mail-io1-xd44.google.com [IPv6:2607:f8b0:4864:20::d44]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 39E4BC0613CE; Fri, 18 Sep 2020 08:01:15 -0700 (PDT) Received: by mail-io1-xd44.google.com with SMTP id r9so7152788ioa.2; Fri, 18 Sep 2020 08:01:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=ueNKaDShpIRFMlqpId/qjUXAnjNovMg7//TW7VMdNwE=; b=HVomqNkH9fjmpdVFa00o7WWRQDW8pd4dSb3yMqpbHDo13MRPJZFYw2nW+N95Bnvx9h uGMlX6rV5lW0Eh6GU3GbpDmxL8/kGsFaQjktmQLAZIdVMdfNLfmZMtzxD2BSSyBB900I W64GHqiXeVAGg4ZuGA4FcyHse/z/ZuHMHW/PqbnbTpanE0H3b7m3mm3kmIZr46ww1Trk mdme9eUeks/VcIYNvO3cViVqWXVZSNsUBLUY0nt0IEg71EBRVZOv6YdzNsFEI9L5vSub AALuUZ1G5y5xXr5RLolDUgb8IpC4BT9a1qRaOjYKutv09nce7VQbFo/p6nzT34DJ8Rro PIBw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=ueNKaDShpIRFMlqpId/qjUXAnjNovMg7//TW7VMdNwE=; b=DhMb7JlMk51mMcUpTYDnwFN8iZ3EeR+AZsp+sFsicrxHfOvvoJN/FV4gRZGchji5fn JzmHrT0pEKbuP2FVV0JbD4Nbh4RBwgsTF0S0Pr5YYlIHsef2cnMotdP7i+n6L4eozv4y e6qjhPe54k06aell1BC1njQZZQURMRcSBR3XGt8h0JZCr7tfZL6L3mnk6iW8Bc8/sCzW QgcrkVtFW4ADvqwjuAYJJM5W0hwnY8MhKG0hOvsRFQzPEocT59IfobTofR4Qsqx2kZR0 p1LdsHOvnj2Ep97yemtfM7jzWyo1QnGM8kQ/iuZm561QBLEhqO15PZwwMJqAPfm3nWT+ bTNQ== X-Gm-Message-State: AOAM532BvGspn/T6GmgQWi38B6k7jIzsmWbt2BHtkHgZDMpB7khKcdKj 1SZzM0LTsZy6aaojINfIb93ZFpgJ7Q5xoL3jHt0= X-Google-Smtp-Source: ABdhPJyznMbeRUByPOlP3l7UP5aSu7ipHEDRQMZC0iihbgUHSRxFze8vy2FEHfUsI1IX+5fuJCUXkrhNgiBNVb2HE1A= X-Received: by 2002:a5e:890c:: with SMTP id k12mr27273847ioj.75.1600441274447; Fri, 18 Sep 2020 08:01:14 -0700 (PDT) MIME-Version: 1.0 References: <20200907155052.2450-1-yazzep@gmail.com> <20200907155052.2450-2-yazzep@gmail.com> <20200908190402.GA797206@rowland.harvard.edu> <20200911151228.GA883311@rowland.harvard.edu> <20200915094531.GA8046@lxhi-065.adit-jv.com> <20200915110111.GA269380@kroah.com> <20200915145258.GC1002979@rowland.harvard.edu> In-Reply-To: From: yasushi asano Date: Sat, 19 Sep 2020 00:00:10 +0900 Message-ID: Subject: Re: [PATCH v3] USB: hub.c: decrease the number of attempts of enumeration scheme To: Alan Stern Cc: Greg KH , Eugeniu Rosca , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, andrew_gabbasov@mentor.com, Baxter Jim , "Natsume, Wataru (ADITJ/SWG)" , "Nishiguchi, Naohiro (ADITJ/SWG)" , =?UTF-8?B?5rWF6YeO5oGt5Y+y?= , kernel test robot , Martin Mueller , Eugeniu Rosca Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org Dear Alan, Could you please proceed with your proposal(Kconfig option)? After all, Customer products need to get USB certification. Thank you for considering my request. 2020=E5=B9=B49=E6=9C=8816=E6=97=A5(=E6=B0=B4) 19:16 yasushi asano : > > Dear Alan > Dear Greg > > Thank you very much for your feedback. > I understood that there is a gap between real system and ideal specificat= ion, > and the Linux community stands on the real system side.(of course). > > I really appreciate your proposal(Kconfig option). > > > But let's start with > > testing the patch I sent you. After all, the first step is to get > > something that does what you want correctly. > > The patch you provided worked fine. > https://marc.info/?l=3Dlinux-usb&m=3D159984230312068&w=3D4 > An excerpt from dmesg is as follows. > It detected the enumeration failure after 27.7seconds since the test star= ted. > so,the PET test passed. [2]-[1] =3D27.7seconds > > [ 111.482541] *** Setting Test Suite *** > [ 130.226648] *** Ready OK Test Start*** > [ 134.808206] usb 1-1.1: new full-speed USB device number 7 using > ehci-platform ... [1] > [ 140.034944] usb 1-1.1: device descriptor read/64, error -110 > [ 140.118069] usb 1-1.1: new full-speed USB device number 8 using ehci-p= latform > [ 145.155142] usb 1-1.1: device descriptor read/64, error -110 > [ 145.163074] usb 1-1-port1: attempt power cycle > [ 147.037094] usb 1-1.1: new full-speed USB device number 9 using ehci-p= latform > [ 152.323168] usb 1-1.1: device descriptor read/64, error -110 > [ 152.407069] usb 1-1.1: new full-speed USB device number 10 using > ehci-platform > [ 157.442518] usb 1-1.1: device not accepting address 10, error -110 > [ 157.527067] usb 1-1.1: new full-speed USB device number 11 using > ehci-platform > [ 162.563123] usb 1-1.1: device not accepting address 11, error -110 > [ 162.571302] usb 1-1-port1: unable to enumerate USB device ... [2] > [ 176.523060] *** End of Test *** > > 2020=E5=B9=B49=E6=9C=8815=E6=97=A5(=E7=81=AB) 23:52 Alan Stern : > > > > On Tue, Sep 15, 2020 at 01:01:11PM +0200, Greg KH wrote: > > > On Tue, Sep 15, 2020 at 11:45:31AM +0200, Eugeniu Rosca wrote: > > > > Dear Alan, > > > > Dear Greg, > > > > > > > > On Fri, Sep 11, 2020 at 11:12:28AM -0400, Alan Stern wrote: > > > > > > > > > The thing is, I'm afraid that without these retry loops, some dev= ices > > > > > will stop working. If that happens, we will not be able to keep = this > > > > > patch in place; we will just have to accept that we fail the PET = test. > > > > > > > > > > Alan Stern > > > > > > > > Does this mean that Linux community leaves no choice but to ship a > > > > forked kernel (with no chance of alignment to upstream) for > > > > organizations which design embedded devices where USB plays a key > > > > role, hence requires passing the USB-IF Compliance Program [*]? > > > > > > We are saying that if you ship such a kernel, we _KNOW_ that it will > > > fail to work in a number of known systems. I doubt you want that to > > > happen if you care about shipping a device, right? > > > > > > > Is there hope to give users a knob (build-time or run-time) which w= ould > > > > enable the behavior expected and thoroughly described in compliance > > > > docs, particularly chapter "6.7.22 A-UUT Device No Response for > > > > connection timeout" of "USB On-The-Go and Embedded Host Automated > > > > Compliance Plan" [**]? > > > > > > Given that the USB-IF has explicitly kicked-out the Linux community f= rom > > > its specification work and orginization, I personally don't really ca= re > > > what they say here. If you are a member of the USB-IF, please work w= ith > > > them to fix the test to reflect real-world systems and not an idealiz= ed > > > system. Last I heard, they wanted nothing to do with Linux systems a= t > > > all :( > > > > If the USB-IF were the final authority regarding USB devices, we > > wouldn't have this problem in the first place. Every device > > would respond properly to the very first port initialization attempt an= d > > no retries would be needed. > > > > But real hardware doesn't always follow the official spec. And then > > when it fails to work with Linux, _we_ are the people who get blamed. > > > > Alan Stern