Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753378AbdG2Dn0 (ORCPT ); Fri, 28 Jul 2017 23:43:26 -0400 Received: from mail-oi0-f46.google.com ([209.85.218.46]:34082 "EHLO mail-oi0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753148AbdG2DnX (ORCPT ); Fri, 28 Jul 2017 23:43:23 -0400 MIME-Version: 1.0 In-Reply-To: References: From: Joel Fernandes Date: Fri, 28 Jul 2017 20:43:22 -0700 Message-ID: Subject: Re: [PATCH V5 2/2] cpufreq: Process remote callbacks from any CPU if the platform permits To: Viresh Kumar Cc: Rafael Wysocki , Peter Zijlstra , Linux PM , Vincent Guittot , Steve Muckle , Juri Lelli , Morten Rasmussen , Patrick Bellasi , eas-dev@lists.linaro.org, Saravana Kannan , LKML 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: 1430 Lines: 38 On Thu, Jul 27, 2017 at 11:46 PM, Viresh Kumar wrote: > On many platforms, CPUs can do DVFS across cpufreq policies. i.e CPU > from policy-A can change frequency of CPUs belonging to policy-B. > > This is quite common in case of ARM platforms where we don't > configure any per-cpu register. > > Add a flag to identify such platforms and update > cpufreq_can_do_remote_dvfs() to allow remote callbacks if this flag is > set. > > Also enable the flag for cpufreq-dt driver which is used only on ARM > platforms currently. > > Signed-off-by: Viresh Kumar > --- > drivers/cpufreq/cpufreq-dt.c | 1 + > include/linux/cpufreq.h | 18 ++++++++++++++++-- > 2 files changed, 17 insertions(+), 2 deletions(-) > > diff --git a/drivers/cpufreq/cpufreq-dt.c b/drivers/cpufreq/cpufreq-dt.c > index fef3c2160691..d83ab94d041a 100644 > --- a/drivers/cpufreq/cpufreq-dt.c > +++ b/drivers/cpufreq/cpufreq-dt.c > @@ -274,6 +274,7 @@ static int cpufreq_init(struct cpufreq_policy *policy) > transition_latency = CPUFREQ_ETERNAL; > > policy->cpuinfo.transition_latency = transition_latency; > + policy->dvfs_possible_from_any_cpu = true; > Are there also ARM hardware that may not support it? If yes, wouldn't a saner thing to do be to keep default as false and read the property from DT for hardware that does support it and then set to true? thanks, -Joel