Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755372AbcKYPzx (ORCPT ); Fri, 25 Nov 2016 10:55:53 -0500 Received: from mail-wm0-f65.google.com ([74.125.82.65]:36608 "EHLO mail-wm0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752149AbcKYPzc (ORCPT ); Fri, 25 Nov 2016 10:55:32 -0500 MIME-Version: 1.0 In-Reply-To: <20161125065529.GB29969@vireshk-i7> References: <2fe61813c867c173ddfcb0b9cabc00a65997a935.1480056714.git.viresh.kumar@linaro.org> <20161125065529.GB29969@vireshk-i7> From: "Rafael J. Wysocki" Date: Fri, 25 Nov 2016 16:55:00 +0100 X-Google-Sender-Auth: w6ePLH_55zd_96ETIqlw3Es-xM0 Message-ID: Subject: Re: [PATCH] PM / OPP: Allow inactive opp_device to be present in dev list To: Viresh Kumar Cc: Rafael Wysocki , jy0922.shim@samsung.com, Viresh Kumar , Nishanth Menon , Stephen Boyd , Lists linaro-kernel , Linux PM , Linux Kernel Mailing List , Stable Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1823 Lines: 42 On Fri, Nov 25, 2016 at 7:55 AM, Viresh Kumar wrote: > On 25-11-16, 12:23, Viresh Kumar wrote: >> Joonyoung Shim reported an interesting problem on his ARM octa-core >> Odoroid-XU3 platform. During system suspend, dev_pm_opp_put_regulator() >> was failing for a struct device for which dev_pm_opp_set_regulator() is >> called earlier. >> >> This happened because an earlier call to >> dev_pm_opp_of_cpumask_remove_table() function (from cpufreq-dt.c file) >> removed all the entries from opp_table->dev_list apart from the last CPU >> device in the cpumask of CPUs sharing the OPP. >> >> But both dev_pm_opp_set_regulator() and dev_pm_opp_put_regulator() >> routines get CPU device for the first CPU in the cpumask. And so the OPP >> core failed to find the OPP table for the struct device. >> >> This patch attempts to fix this problem by adding another field in the >> struct opp_device: inactive. >> >> Instead of removing the entries from the list during >> dev_pm_opp_of_cpumask_remove_table() function call, we mark them as >> inactive. Such inactive devices will not be used by the core in most of >> the cases, like before, but will be used only at special places which >> need to take inactive devices into account. >> >> All the devices are removed from the list together now and that happens >> only when the opp_table gets destroyed. >> >> This patch is tested on Dual A15, Exynos5250 platform by compiling the >> cpufreq-dt driver as a module. The module is inserted/removed multiple >> times with combinations of CPU offline/online steps. >> >> Signed-off-by: Viresh Kumar > > @Rafael: Can you please add following while applying the patch ? > > Cc: # v4.4+ Yes, I can, but I need an ACK for this from Stephen too. Thanks, Rafael