From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755544Ab3KVNNT (ORCPT ); Fri, 22 Nov 2013 08:13:19 -0500 Received: from v094114.home.net.pl ([79.96.170.134]:62276 "HELO v094114.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1752069Ab3KVNNS (ORCPT ); Fri, 22 Nov 2013 08:13:18 -0500 From: "Rafael J. Wysocki" To: Viresh Kumar Cc: Stephen Warren , Kukjin Kim , Amit Daniel Kachhap , Sachin Kamat , Lists linaro-kernel , Patch Tracking , "cpufreq@vger.kernel.org" , "linux-pm@vger.kernel.org" , Linux Kernel Mailing List , Lan Tianyu , Nishanth Menon , jinchoi@broadcom.com, Sebastian Capella Subject: Re: [PATCH V2 2/2] cpufreq: Change freq before suspending governors Date: Fri, 22 Nov 2013 14:25:59 +0100 Message-ID: <4592811.7DNNYfo4cW@vostro.rjw.lan> User-Agent: KMail/4.10.5 (Linux/3.12.0-rc6+; KDE/4.10.5; x86_64; ; ) In-Reply-To: References: <2783049.JzUB2QcsZz@vostro.rjw.lan> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Friday, November 22, 2013 06:22:52 PM Viresh Kumar wrote: > On 22 November 2013 18:07, Rafael J. Wysocki wrote: > > On Friday, November 22, 2013 04:59:49 PM Viresh Kumar wrote: > >> Some platforms might want to change frequency before suspending governors. Like: > >> - Some platform which want to set freq to max to speed up suspend/hibernation > >> process. > >> - Some platform (like: Tegra or exynos), set this to min or bootloader's > >> frequency. > >> > >> This patch adds an option for those, so that they can specify this at call to > >> ->init(), so that cpufreq core can take care of this before suspending system. > >> > >> If this variable is not updated by ->init() then its value would be zero and so > >> core wouldn't do anything. > >> > >> Signed-off-by: Viresh Kumar > > > > I don't think this is generally necessary, because the suspend/resume routines > > added by patch [1/2] will be executed very late during suspend or very early > > during resume and it shouldn't really matter what performance levels the CPUs > > are at then. > > There are few things here: > - I feel that the current place from where we have suspended stuff is not gonna > fly. We are doing that in noirq and probably devices which might be required > during frequency transitions might already be down.. So we *may* need to > move that in dpm_suspend().. That would be a much more intrusive change. Definitely not 3.13 material at this point. Thanks! -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center.