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 22505C3279B for ; Tue, 10 Jul 2018 19:14:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D4D49208E8 for ; Tue, 10 Jul 2018 19:14:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ti.com header.i=@ti.com header.b="M1WaHjLJ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D4D49208E8 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 S1732673AbeGJTOr (ORCPT ); Tue, 10 Jul 2018 15:14:47 -0400 Received: from fllv0015.ext.ti.com ([198.47.19.141]:36998 "EHLO fllv0015.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732502AbeGJTOr (ORCPT ); Tue, 10 Jul 2018 15:14:47 -0400 Received: from dlelxv90.itg.ti.com ([172.17.2.17]) by fllv0015.ext.ti.com (8.15.2/8.15.2) with ESMTP id w6AJE0Nq080691; Tue, 10 Jul 2018 14:14:00 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1531250040; bh=SldqOA8lT+zRIGArWhumukQTJWXMCoY3ACqrkm6R+T8=; h=Subject:To:References:CC:From:Date:In-Reply-To; b=M1WaHjLJK22aFHuZQ1LK13VHCZH0F8WLRvXvWlJHxbLaLFVOxNdBw4mxT29A3nRHI qQ/VkHOMuXXL8WIynVxbKkuwmRWQeBBqnqMfz1YXLF6RoBrWm3EM7HSPW9c1PLzARr XpS5BVXV4f4zrD2KzqRT5imtoNnrsfVTGHdKdHJM= Received: from DLEE112.ent.ti.com (dlee112.ent.ti.com [157.170.170.23]) by dlelxv90.itg.ti.com (8.14.3/8.13.8) with ESMTP id w6AJE0SG011710; Tue, 10 Jul 2018 14:14:00 -0500 Received: from DLEE113.ent.ti.com (157.170.170.24) by DLEE112.ent.ti.com (157.170.170.23) 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 14:14:00 -0500 Received: from dlep33.itg.ti.com (157.170.170.75) by DLEE113.ent.ti.com (157.170.170.24) 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 14:14:00 -0500 Received: from [172.24.190.233] (ileax41-snat.itg.ti.com [10.172.224.153]) by dlep33.itg.ti.com (8.14.3/8.13.8) with ESMTP id w6AJDusE025610; Tue, 10 Jul 2018 14:13:57 -0500 Subject: Re: [PATCH v2] driver core: Partially revert "driver core: correct device's shutdown order" To: Greg Kroah-Hartman , "Rafael J. Wysocki" References: <1530600642-25090-1-git-send-email-kernelfans@gmail.com> <8816662.k3KXbdkA2e@aspire.rjw.lan> <2927655.Y1qg3UnIrE@aspire.rjw.lan> <5284251.Resgjlja2Q@aspire.rjw.lan> <20180710125956.GA25343@kroah.com> <20180710154715.GA20793@kroah.com> CC: "Rafael J. Wysocki" , Pingfan Liu , Linux Kernel Mailing List , Grygorii Strashko , Christoph Hellwig , Bjorn Helgaas , Dave Young , Linux PCI , Lukas Wunner , Linux PM From: Kishon Vijay Abraham I Message-ID: Date: Wed, 11 Jul 2018 00:43:55 +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: <20180710154715.GA20793@kroah.com> 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 09:17 PM, Greg Kroah-Hartman wrote: > On Tue, Jul 10, 2018 at 05:40:21PM +0200, Rafael J. Wysocki wrote: >> On Tue, Jul 10, 2018 at 2:59 PM, Greg Kroah-Hartman >> wrote: >>> On Tue, Jul 10, 2018 at 02:51:33PM +0200, 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 covered an issue >>>> with system shutdown, while system-wide suspend/resume potentially >>>> had the same issue on the affected platforms (which was not covered). >>>> >>>> Moreover, the shutdown issue originally addressed by the change in >>>> really_probe() made by commit 52cdbdd49853 is not present in 4.18-rc >>>> any more, since dra7 started to use the sdhci-omap driver which >>>> doesn't disable any regulators during shutdown, so the really_probe() >>>> part of commit 52cdbdd49853 can be safely reverted. [The original >>>> issue was related to the omap_hsmmc driver used by dra7 previously.] >>>> >>>> For the above reasons, revert the really_probe() modifications made >>>> by commit 52cdbdd49853. >>>> >>>> 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 >>>> Reviewed-by: Kishon Vijay Abraham I >>>> Signed-off-by: Rafael J. Wysocki >>>> --- >>>> >>>> -> v2: Added information from Kishon on the fact that it should be safe >>>> to revert the really_probe() modifications added by the >>>> problematic commit. Also added the Reviewed-by tag from Kishon. >>> >>> Looks good to me, want me to queue it up in my tree, or are you going to >>> send it on to Linus? >> >> Please queue it up. >> >>> And shouldn't this have a stable tag as well? >> >> That is sort of a gray area, because I think it may expose the >> shutdown issue on dra7 in -stable, but technically it still fixes a >> regression in the driver core. So your call I suppose. :-) > > Being bug compatible is key :) > > I'll add a stable tag. sure. If I see the issue in dra7, I'll send a stable fix in omap_hsmmmc driver. Thanks Kishon