Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754540AbcJKWis (ORCPT ); Tue, 11 Oct 2016 18:38:48 -0400 Received: from mail-vk0-f49.google.com ([209.85.213.49]:33576 "EHLO mail-vk0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753342AbcJKWiq (ORCPT ); Tue, 11 Oct 2016 18:38:46 -0400 MIME-Version: 1.0 In-Reply-To: <12733315.XoNTxDd2zv@vostro.rjw.lan> References: <1476220320-19685-1-git-send-email-hotran@apm.com> <12733315.XoNTxDd2zv@vostro.rjw.lan> From: Hoan Tran Date: Tue, 11 Oct 2016 15:31:36 -0700 Message-ID: Subject: Re: [PATCH] cpufreq: CPPC: Correct desired_perf calculation To: "Rafael J. Wysocki" Cc: Viresh Kumar , Prashanth Prakash , Al Stone , linux-pm@vger.kernel.org, lkml , Loc Ho , Duc Dang Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1351 Lines: 45 Hi Rafael, On Tue, Oct 11, 2016 at 2:50 PM, Rafael J. Wysocki wrote: > On Tuesday, October 11, 2016 02:12:00 PM Hoan Tran wrote: >> The desired_perf is an abstract performance number. Its value should >> be in the range of [lowest perf, highest perf] of CPPC. >> The correct calculation is >> desired_perf = freq * cppc_highest_perf / cppc_dmi_max_khz >> >> Signed-off-by: Hoan Tran >> --- >> drivers/cpufreq/cppc_cpufreq.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c >> index 1b2f28f..ab1d4b7 100644 >> --- a/drivers/cpufreq/cppc_cpufreq.c >> +++ b/drivers/cpufreq/cppc_cpufreq.c >> @@ -84,7 +84,7 @@ static int cppc_cpufreq_set_target(struct cpufreq_policy *policy, >> >> cpu = all_cpu_data[policy->cpu]; >> >> - cpu->perf_ctrls.desired_perf = (u64)target_freq * policy->max / cppc_dmi_max_khz; >> + cpu->perf_ctrls.desired_perf = (u64)target_freq * cpu->perf_caps.highest_perf / cppc_dmi_max_khz; >> freqs.old = policy->cur; >> freqs.new = target_freq; >> >> > > This patch has already been applied AFAICS. > You mean this applied patch "cpufreq: CPPC: Avoid overflow when calculating desired_perf" This is another the bug, not the overflow bug. Thanks Hoan > Thanks, > Rafael >