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=-0.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,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 EAA30C3279B for ; Tue, 10 Jul 2018 12:23:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A1E6220883 for ; Tue, 10 Jul 2018 12:23:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ti.com header.i=@ti.com header.b="RC8F4LKw" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A1E6220883 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=ti.com 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 S933293AbeGJMW7 (ORCPT ); Tue, 10 Jul 2018 08:22:59 -0400 Received: from lelv0142.ext.ti.com ([198.47.23.249]:49308 "EHLO lelv0142.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753275AbeGJMW5 (ORCPT ); Tue, 10 Jul 2018 08:22:57 -0400 Received: from dflxv15.itg.ti.com ([128.247.5.124]) by lelv0142.ext.ti.com (8.15.2/8.15.2) with ESMTP id w6ACMWZD122173; Tue, 10 Jul 2018 07:22:32 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1531225353; bh=uJ507R84Xt3W5o9Pkyn0fon8FDpGq97Xuu6z1pb6AjY=; h=Subject:To:References:CC:From:Date:In-Reply-To; b=RC8F4LKwdPWJJsGX/G9gd0lXuCDqf3sQ6BF3QuKiYRWDqXMhJMSEOA00XPh8gnCi7 XOvWvjl33MctvBVcTRcqwj4oBwGpzsVWUWbXPtufRpg9GNW1zVVSYWgk05ZekEkmQP Fa4CFyoUuslgr4TEvQUirmi6LJdyJCk7DHBeVJKw= Received: from DFLE108.ent.ti.com (dfle108.ent.ti.com [10.64.6.29]) by dflxv15.itg.ti.com (8.14.3/8.13.8) with ESMTP id w6ACMWvE015851; Tue, 10 Jul 2018 07:22:32 -0500 Received: from DFLE115.ent.ti.com (10.64.6.36) by DFLE108.ent.ti.com (10.64.6.29) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1466.3; Tue, 10 Jul 2018 07:22:32 -0500 Received: from dlep32.itg.ti.com (157.170.170.100) by DFLE115.ent.ti.com (10.64.6.36) with Microsoft SMTP Server (version=TLS1_0, cipher=TLS_RSA_WITH_AES_256_CBC_SHA) id 15.1.1466.3 via Frontend Transport; Tue, 10 Jul 2018 07:22:32 -0500 Received: from [172.24.190.233] (ileax41-snat.itg.ti.com [10.172.224.153]) by dlep32.itg.ti.com (8.14.3/8.13.8) with ESMTP id w6ACMS2i022797; Tue, 10 Jul 2018 07:22:29 -0500 Subject: Re: [PATCH] driver core: Partially revert "driver core: correct device's shutdown order" To: "Rafael J. Wysocki" , Greg Kroah-Hartman References: <1530600642-25090-1-git-send-email-kernelfans@gmail.com> <8816662.k3KXbdkA2e@aspire.rjw.lan> <2927655.Y1qg3UnIrE@aspire.rjw.lan> CC: Pingfan Liu , , Grygorii Strashko , Christoph Hellwig , Bjorn Helgaas , Dave Young , , Lukas Wunner , Linux PM From: Kishon Vijay Abraham I Message-ID: Date: Tue, 10 Jul 2018 17:52:28 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: <2927655.Y1qg3UnIrE@aspire.rjw.lan> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On Tuesday 10 July 2018 05:05 PM, Rafael J. Wysocki wrote: > From: Rafael J. Wysocki > > Commit 52cdbdd49853 (driver core: correct device's shutdown order) > introduced a regression by breaking device shutdown on some systems. > > Namely, the devices_kset_move_last() call in really_probe() added by > that commit is a mistake as it may cause parents to follow children > in the devices_kset list which then causes shutdown to fail. For > example, if a device has children before really_probe() is called > for it (which is not uncommon), that call will cause it to be > reordered after the children in the devices_kset list and the > ordering of that list will not reflect the correct device shutdown > order any more. > > Also it causes the devices_kset list to be constantly reordered > until all drivers have been probed which is totally pointless > overhead in the majority of cases and it only covers an issue > with system shutdown, while system-wide suspend/resume potentially > has the same issue on the affected platforms (which is not covered). > > For that reason, revert the really_probe() modifications made by > commit 52cdbdd49853 which unfortunately will expose the shutdown > issue the problematic commit attempted to fix (and which will have > to be addressed differently and correctly in the future). > > The other code changes made by commit 52cdbdd49853 are useful and > they need not be reverted. > > Fixes: 52cdbdd49853 (driver core: correct device's shutdown order) > Link: https://lore.kernel.org/lkml/CAFgQCTt7VfqM=UyCnvNFxrSw8Z6cUtAi3HUwR4_xPAc03SgHjQ@mail.gmail.com/ > Reported-by: Pingfan Liu > Tested-by: Pingfan Liu > Signed-off-by: Rafael J. Wysocki > --- This issue because of which 52cdbdd49853 (driver core: correct device's shutdown order) was added is not present from 4.18, since dra7 started using sdhci-omap.c driver which doesn't disable regulator during shutdown. (The original issue was present in omap_hsmmc driver). When sdhci-omap driver is modified to disable regulator during shutdown, something like device_link_add() can be added in _regulator_get(). Since this doesn't reintroduce the problem that was solved by 52cdbdd49853, this can be safely merged. Reviewed-by: Kishon Vijay Abraham I Thanks Kishon