Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1752251AbdGGRGg (ORCPT <rfc822;w@1wt.eu>);
        Fri, 7 Jul 2017 13:06:36 -0400
Received: from foss.arm.com ([217.140.101.70]:49676 "EHLO foss.arm.com"
        rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
        id S1750726AbdGGRGe (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
        Fri, 7 Jul 2017 13:06:34 -0400
Subject: Re: [PATCH v2 02/10] cpufreq: provide data for frequency-invariant
 load-tracking support
To: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Viresh Kumar <viresh.kumar@linaro.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linux PM <linux-pm@vger.kernel.org>,
        Russell King - ARM Linux <linux@arm.linux.org.uk>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Russell King <rmk+kernel@armlinux.org.uk>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will.deacon@arm.com>, Juri Lelli <juri.lelli@arm.com>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Morten Rasmussen <morten.rasmussen@arm.com>,
        "Rafael J . Wysocki" <rjw@rjwysocki.net>
References: <20170706094948.8779-1-dietmar.eggemann@arm.com>
 <20170706094948.8779-3-dietmar.eggemann@arm.com>
 <20170706104027.GB13048@vireshk-i7>
 <c92f1bd0-6611-8eec-51d7-f6d7754a5870@arm.com>
 <CAJZ5v0gBPNDBYWbuHVaB7deNHSZKziaAeybSw3mg+S8V_roO-Q@mail.gmail.com>
From: Dietmar Eggemann <dietmar.eggemann@arm.com>
Message-ID: <22f004af-0158-8265-2da5-34743f294bfb@arm.com>
Date: Fri, 7 Jul 2017 18:06:30 +0100
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101
 Thunderbird/52.1.1
MIME-Version: 1.0
In-Reply-To: <CAJZ5v0gBPNDBYWbuHVaB7deNHSZKziaAeybSw3mg+S8V_roO-Q@mail.gmail.com>
Content-Type: text/plain; charset=utf-8
Content-Language: en-GB
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org
Content-Length: 784
Lines: 22

On 07/07/17 17:18, Rafael J. Wysocki wrote:
> On Fri, Jul 7, 2017 at 6:01 PM, Dietmar Eggemann
> <dietmar.eggemann@arm.com> wrote:
>> On 06/07/17 11:40, Viresh Kumar wrote:
>>> On 06-07-17, 10:49, Dietmar Eggemann wrote:

[...]

>> So what about I call arch_set_freq_scale() in __cpufreq_notify_transition() in the
>> CPUFREQ_POSTCHANGE case for slow-switching and in cpufreq_driver_fast_switch() for
>> fast-switching?
> 
> Why don't you do this in drivers instead of in the core?
> 
> Ultimately, the driver knows what frequency it has requested, so why
> can't it call arch_set_freq_scale()?

That's correct but for arm/arm64 we have a lot of different cpufreq
drivers to deal with. And doing this call to arch_set_freq_scale() once
in the cpufreq core will cover them all.

[...]