Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934355AbcJMRmS (ORCPT ); Thu, 13 Oct 2016 13:42:18 -0400 Received: from mail-pf0-f172.google.com ([209.85.192.172]:32880 "EHLO mail-pf0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934303AbcJMRmF (ORCPT ); Thu, 13 Oct 2016 13:42:05 -0400 From: Hoan Tran To: "Rafael J. Wysocki" , Viresh Kumar , pprakash@codeaurora.org, Al Stone Cc: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, lho@apm.com, Duc Dang , Hoan Tran Subject: [PATCH v2] cpufreq: CPPC: Correct desired_perf calculation Date: Thu, 13 Oct 2016 10:33:35 -0700 Message-Id: <1476380015-21001-1-git-send-email-hotran@apm.com> X-Mailer: git-send-email 1.9.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1331 Lines: 42 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 And cppc_cpufreq_set_target() returns if desired_perf is exactly the same with the old perf. Signed-off-by: Hoan Tran --- v2 * Return if desired_perf is the same with the old one (Prashanth's suggestion) drivers/cpufreq/cppc_cpufreq.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c index 1b2f28f..4852d9e 100644 --- a/drivers/cpufreq/cppc_cpufreq.c +++ b/drivers/cpufreq/cppc_cpufreq.c @@ -80,11 +80,17 @@ static int cppc_cpufreq_set_target(struct cpufreq_policy *policy, { struct cppc_cpudata *cpu; struct cpufreq_freqs freqs; + u32 desired_perf; int ret = 0; cpu = all_cpu_data[policy->cpu]; - cpu->perf_ctrls.desired_perf = (u64)target_freq * policy->max / cppc_dmi_max_khz; + desired_perf = (u64)target_freq * cpu->perf_caps.highest_perf / cppc_dmi_max_khz; + /* Return if it is exactly the same perf */ + if (desired_perf == cpu->perf_ctrls.desired_perf) + return ret; + + cpu->perf_ctrls.desired_perf = desired_perf; freqs.old = policy->cur; freqs.new = target_freq; -- 1.9.1