Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752267AbaBQJF2 (ORCPT ); Mon, 17 Feb 2014 04:05:28 -0500 Received: from e28smtp08.in.ibm.com ([122.248.162.8]:49376 "EHLO e28smtp08.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751976AbaBQJF0 (ORCPT ); Mon, 17 Feb 2014 04:05:26 -0500 Message-ID: <5301CF89.5070803@linux.vnet.ibm.com> Date: Mon, 17 Feb 2014 14:29:53 +0530 From: "Srivatsa S. Bhat" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:15.0) Gecko/20120828 Thunderbird/15.0 MIME-Version: 1.0 To: Viresh Kumar CC: "Rafael J. Wysocki" , Lists linaro-kernel , "cpufreq@vger.kernel.org" , "linux-pm@vger.kernel.org" , Linux Kernel Mailing List , Pierre Ossman Subject: Re: [PATCH 2/2] cpufreq: don't call cpufreq_update_policy() on CPU addition References: <15ccc0609cb9ee3db0ad3a95b29bf69d11ea197c.1392375504.git.viresh.kumar@linaro.org> <8f2fc4d6240b567fdb69a0b47f073d174b7ef9b2.1392375504.git.viresh.kumar@linaro.org> <5301CBAE.3000102@linux.vnet.ibm.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14021709-2000-0000-0000-00000FC2E801 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/17/2014 02:24 PM, Viresh Kumar wrote: > 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. > Ah, I see. >> 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 :) > Ok.. Regards, Srivatsa S. Bhat -- 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/