Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752209AbaBQIyq (ORCPT ); Mon, 17 Feb 2014 03:54:46 -0500 Received: from mail-ob0-f169.google.com ([209.85.214.169]:65349 "EHLO mail-ob0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751851AbaBQIyo (ORCPT ); Mon, 17 Feb 2014 03:54:44 -0500 MIME-Version: 1.0 In-Reply-To: <5301CBAE.3000102@linux.vnet.ibm.com> References: <15ccc0609cb9ee3db0ad3a95b29bf69d11ea197c.1392375504.git.viresh.kumar@linaro.org> <8f2fc4d6240b567fdb69a0b47f073d174b7ef9b2.1392375504.git.viresh.kumar@linaro.org> <5301CBAE.3000102@linux.vnet.ibm.com> Date: Mon, 17 Feb 2014 14:24:43 +0530 Message-ID: Subject: Re: [PATCH 2/2] cpufreq: don't call cpufreq_update_policy() on CPU addition From: Viresh Kumar To: "Srivatsa S. Bhat" Cc: "Rafael J. Wysocki" , Lists linaro-kernel , "cpufreq@vger.kernel.org" , "linux-pm@vger.kernel.org" , Linux Kernel Mailing List , Pierre Ossman Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 17 February 2014 14:13, Srivatsa S. Bhat wrote: > On 02/14/2014 04:30 PM, Viresh Kumar wrote: >> cpufreq_update_policy() is called from two places currently. From a workqueue >> handled queued from cpufreq_bp_resume() for boot CPU and from >> cpufreq_cpu_callback() whenever a CPU is added. >> >> The first one makes sure that boot CPU is running on the frequency present in >> policy->cpu. But we don't really need a call from cpufreq_cpu_callback(), >> because we always call cpufreq_driver->init() (which will set policy->cur >> correctly) whenever first CPU of any policy is added back. And so every policy >> structure is guaranteed to have the right frequency in policy->cur. >> > > This wording is slightly inaccurate. ->init() may or may not set policy->cur > (for example, powernowk8 driver doesn't set it in the init routine).. Its not the wording that is wrong but this particular driver then :) This is what Documentation/cpu-drivers.txt says: 1.2 Per-CPU Initialization Then, the driver must fill in the following values: policy->cur The current operating frequency of this CPU (if appropriate) And so it is supposed to do it. > But we set it for sure in __cpufreq_add_dev(): > > 1117 if (cpufreq_driver->get) { > 1118 policy->cur = cpufreq_driver->get(policy->cpu); > 1119 if (!policy->cur) { > 1120 pr_err("%s: ->get() failed\n", __func__); > 1121 goto err_get_freq; > 1122 } > 1123 } Its just about removing that from drivers and doing it once in core :) >> Signed-off-by: Viresh Kumar > > The reasoning and the code looks good to me. > > Reviewed-by: Srivatsa S. Bhat Thanks. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/