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=-1.7 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 3071EC43441 for ; Sun, 11 Nov 2018 19:26:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CCE46214DB for ; Sun, 11 Nov 2018 19:26:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="alIXFYdd" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CCE46214DB Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726308AbeKLFQH (ORCPT ); Mon, 12 Nov 2018 00:16:07 -0500 Received: from mail.kernel.org ([198.145.29.99]:44890 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725725AbeKLFQH (ORCPT ); Mon, 12 Nov 2018 00:16:07 -0500 Received: from mail-wr1-f52.google.com (mail-wr1-f52.google.com [209.85.221.52]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 51BAD214DB for ; Sun, 11 Nov 2018 19:26:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1541964403; bh=X10YEJkC8D15qhUL9Ww7BEAr07FvgseH/o7dM7LZqno=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=alIXFYdd/OQ2khf42mYQbOZpUE6xQKsZPSywZQUVZvTRczkw0TSKrVmjoT7Mw3CFp +mpKiHHKZ+7ePQhZf8UjbJ97o6f8TeYN1LsCDkoKWXvgYsc0UArgnD4/z06chzfneF lAa1bVXimjmlXikuGu/Bwx2m5fpiYwjd2wrT7Zi4= Received: by mail-wr1-f52.google.com with SMTP id o15-v6so7020672wrv.4 for ; Sun, 11 Nov 2018 11:26:43 -0800 (PST) X-Gm-Message-State: AGRZ1gKFK4ZhMBLdvhDpkP1vsk0iwPigfnYSa9cTMf393gjfCPvvEghM /AJIMCzv0MJM2NO2hQzlpqlQiWwKzs34EHhT2dwbzg== X-Google-Smtp-Source: AJdET5fo15kfDtR4opQa6G6wEsOGoIo9KbArby5L2oUbv/p95wEfRgr2/GqHHpXVzvpfDHfAYTwwGMA8z6uCIjg2Ixk= X-Received: by 2002:a5d:410d:: with SMTP id l13-v6mr14834309wrp.61.1541964401798; Sun, 11 Nov 2018 11:26:41 -0800 (PST) MIME-Version: 1.0 References: <20181110181101.24557-1-andriy.shevchenko@linux.intel.com> In-Reply-To: From: Rob Herring Date: Sun, 11 Nov 2018 13:26:30 -0600 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v1 1/5] drivercore: Revert "deferral race condition fix" To: Andy Shevchenko Cc: andriy.shevchenko@linux.intel.com, "Rafael J. Wysocki" , Greg Kroah-Hartman , Linux Kernel Mailing List , Hans de Goede , peter.ujfalusi@ti.com, a.hajda@samsung.com, Grant Likely Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Nov 11, 2018 at 7:04 AM Andy Shevchenko wrote: > > I seems Grant's mail delivery bounces messages. I delibirately reduced > the Cc list for sake of ping Grant in case it would pass. That would be because he is not at Linaro anymore. Added his ARM account. > On Sat, Nov 10, 2018 at 8:12 PM Andy Shevchenko > wrote: > > > > Consider the following scenario. > > > > There are two independent devices coupled together by functional dependencies: > > - USB OTG (dwc3-pci) > > - extcon (tested with extcon-intel-mrfld, not yet in upstream) > > > > Each of the driver services a corresponding device is built as a module. In the > > Buildroot environment the modules are probed by alphabetical ordering of their > > modaliases. The latter comes to the case when USB OTG driver will be probed > > first followed by extcon one. > > > > So, if the platform anticipates extcon device to be appeared, in the above case > > we will get deferred probe of USB OTG, because of ordering. > > > > Now, a cherry on top of the cake, the deferred probing list contains > > the only two modules, i.e. USB OTG and extcon. Due to above circumstances, > > values in the local_trigger_count and deferred_trigger_count are not the same, > > and thus provokes deferred probe triggering again and again. > > > > ... > > [ 20.678332] platform dwc3.0.auto: Retrying from deferred list > > [ 20.694743] platform dwc3.0.auto: Driver dwc3 requests probe deferral > > [ 20.701254] platform dwc3.0.auto: Added to deferred list > > [ 20.706620] platform dwc3.0.auto: driver_deferred_probe_add_trigger 1 2 > > [ 20.713732] platform dwc3.0.auto: Retrying from deferred list > > [ 20.730035] platform dwc3.0.auto: Driver dwc3 requests probe deferral > > [ 20.736540] platform dwc3.0.auto: Added to deferred list > > [ 20.741889] platform dwc3.0.auto: driver_deferred_probe_add_trigger 3 4 > > [ 20.748991] platform dwc3.0.auto: Retrying from deferred list > > [ 20.765416] platform dwc3.0.auto: Driver dwc3 requests probe deferral > > [ 20.771914] platform dwc3.0.auto: Added to deferred list > > [ 20.777279] platform dwc3.0.auto: driver_deferred_probe_add_trigger 5 6 > > ... > > > > Deeper investigation shows the culprit commit 58b116bce136 > > ("drivercore: deferral race condition fix") which was dedicated to fix some > > other issue while bringing a regression. > > > > This reverts commit 58b116bce13612e5aa6fcd49ecbd4cf8bb59e835 for good until > > we will have better solution. How is behavior that's been there for 4.5 years a regression? Aren't we going to break Davinci that this commit was supposed to fix? What else could be relying on current behavior? Rob