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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT 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 F0BE8C3279B for ; Tue, 10 Jul 2018 15:47:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AFF75208F7 for ; Tue, 10 Jul 2018 15:47:22 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AFF75208F7 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.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 S934173AbeGJPrU (ORCPT ); Tue, 10 Jul 2018 11:47:20 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:49972 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933132AbeGJPrS (ORCPT ); Tue, 10 Jul 2018 11:47:18 -0400 Received: from localhost (LFbn-1-12247-202.w90-92.abo.wanadoo.fr [90.92.61.202]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id E1185C9D; Tue, 10 Jul 2018 15:47:17 +0000 (UTC) Date: Tue, 10 Jul 2018 17:47:15 +0200 From: Greg Kroah-Hartman To: "Rafael J. Wysocki" Cc: "Rafael J. Wysocki" , Pingfan Liu , Linux Kernel Mailing List , Grygorii Strashko , Christoph Hellwig , Bjorn Helgaas , Dave Young , Linux PCI , Lukas Wunner , Linux PM , Kishon Vijay Abraham I Subject: Re: [PATCH v2] driver core: Partially revert "driver core: correct device's shutdown order" Message-ID: <20180710154715.GA20793@kroah.com> 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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.0 (2018-05-17) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. thanks, greg k-h