From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wang Weidong Subject: Re: [PATCH 0/2] fix some problems for cpufreq Date: Sun, 30 Nov 2014 16:23:59 +0800 Message-ID: <547AD41F.7030907@huawei.com> References: <1417142619-14548-1-git-send-email-wangweidong1@huawei.com> <2248504.pAVebap2qN@vostro.rjw.lan> <547923F2.6000701@huawei.com> <4004530.x5fm24OG42@vostro.rjw.lan> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: Received: from szxga01-in.huawei.com ([119.145.14.64]:46291 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751846AbaK3IYS (ORCPT ); Sun, 30 Nov 2014 03:24:18 -0500 In-Reply-To: <4004530.x5fm24OG42@vostro.rjw.lan> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: "Rafael J. Wysocki" Cc: viresh.kumar@linaro.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, guohanjun@huawei.com On 2014/11/30 6:30, Rafael J. Wysocki wrote: > On Saturday, November 29, 2014 09:40:02 AM Wang Weidong wrote: >> On 2014/11/29 9:26, Rafael J. Wysocki wrote: >>> On Friday, November 28, 2014 10:43:37 AM Wang Weidong wrote: >>>> Hi Rafael and Viresh >>>> >>>> Sorry to trouble you again. As for: >>>> "acpi-cpufreq: get the cur_freq from acpi_processor_performance states" >>>> I do it again, and add the other patch. >>>> >>>> patch #1: acpi-cpufreq: make the freq_table store the same freq value >>>> >>>> I think it can work. The set of available states which come >>>> from acpi won't change. Just like the power would be remove, >>>> the acpi driver will do that: >>>> call >>>> ->acpi_processor_ppc_has_changed >>>> ->cpufreq_update_policy >>>> ->acpi_ppc_notifier_block.notifier_call >>>> ->acpi_processor_ppc_notifier >>>> ->cpufreq_verify_within_limits >>>> The progress will change the policy's min_freq and max_freq >>>> while it won't change the set of states(freq_tables). >>> >>> OK, so the above information needs to go into the changelog of patch [1/2]. >>> Also, please clarify the problem description in that changelog, it is very >>> difficult to understand the way it is now. >>> >> >> sure, I should do it. >> >>>> patch #2: cpufreq: show the real avail freqs with the freq_table >>>> >>>> when the min_freq and max_freq change, we should sync the availble >>>> freqs. >>> >>> Why? Do any other cpufreq drivers do that? >>> >> >> If some cpufreq drivers support several freqs like this: >> 1.05 Ghz 1.30Ghz 1.70GHz 2.10GHz 2.3GHz >> | | >> min max >> So what the available freqs is 1.30GHz 1.70GHz 2.10GHz >> >> when we do cpufreq-info or cat scaling_available_frequencies, >> I think the available freqs table show only show these 3 value, >> not all the values. > > That changes an existing user space interface, however, and the > only reason I can figure out from what you're saying is your personal > opinion. This isn't a good enough reason, however. > > What if there are utilities and scripts out there relying on the > current behavior? > No, there are not utilities and scripts relying on it. I just confuse that: If the policy->min and policy-max is changed while it shows all available freqs though scaling_available_frequencies. I can't set all freq-steps, only [policy->min, policy->max]. why should it show all the available freqs. Although, it doesn't impact on us. So just ignore the patch#2. :) Wang, Regards >