From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755574AbcCUMZi (ORCPT ); Mon, 21 Mar 2016 08:25:38 -0400 Received: from lists.s-osg.org ([54.187.51.154]:55072 "EHLO lists.s-osg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755457AbcCUMZe (ORCPT ); Mon, 21 Mar 2016 08:25:34 -0400 Subject: Re: [PATCH] regulator: Lookup unresolved parent supplies before regulators cleanup To: Mark Brown References: <1458527986-4576-1-git-send-email-javier@osg.samsung.com> <20160321111100.GN2566@sirena.org.uk> <56EFE583.6000807@osg.samsung.com> Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, Liam Girdwood , Bjorn Andersson From: Javier Martinez Canillas Message-ID: <56EFE836.3010606@osg.samsung.com> Date: Mon, 21 Mar 2016 09:25:26 -0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 In-Reply-To: <56EFE583.6000807@osg.samsung.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/21/2016 09:13 AM, Javier Martinez Canillas wrote: > [adding Bjorn Andersson who is the author of commit 6261b06de565] > I got a user invalid error when sending to the email address that Bjorn used in that commit, so I'm re-sending to his latest address. Sorry for the spam. Bjorn, here is the email archive in case you need more context: https://lkml.org/lkml/2016/3/20/277 > Hello Mark, > > Thanks a lot for your feedback. > > On 03/21/2016 08:11 AM, Mark Brown wrote: >> On Sun, Mar 20, 2016 at 11:39:46PM -0300, Javier Martinez Canillas wrote: >> >>> Unfortunately, that changed the behavior of the regulator core since now a >>> parent supply with a child regulator marked as always-on, won't be enabled >>> unless a client driver attempts to get the child regulator during boot. >> >>> This patch makes the unresolved parent supplies to be looked up before the >>> regulators late cleanup, so those with a child marked as always on will be >>> enabled regardless if a driver attempted to get the child regulator or not. >> >> This doesn't make much sense to me as a fix - it feels like we're doing >> a fragile hack. Surely it's better to do this as we register the >> devices, that way we're also protected against any similar issues with > > Sorry, not sure if I understood correctly. You mean to do it when the > drivers register the regulators, so at regulator_register() ? > > That's basically what was done before Bjorn's patch but that doesn't > handle the case of out of order registration when having circular > dependencies between regulators. > >> this that might occur after late probe if things are built modular? Or > > Someone told me once that modules are always a special case :) > >> is there a strong reason for doing this only at late_initcall? >> > > The reason why I did in late_initcall / regulator_init_complete is that > the problem for me is that unused regulators are disabled on cleanup but > parents whose childrens are marked as always on should be keep enabled. > > But these are disabled anyways just because the regulator core didn't know > about that dependency. So doing it before the late cleanup sounded like a > good solution for me. > > Now if you think that's a hack and have another approach in mind, then I'll > gladly try to implement it instead, if you could please elaborate on that. > Best regards, -- Javier Martinez Canillas Open Source Group Samsung Research America