linux-kernel - [PATCH 6/6] thermal/cpu_cooling: update policy limits if clipped

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Message-Id: <5a3411e7341a4208d0d67c0c5ea2208a4c5ee658.1438239727.git.viresh.kumar@linaro.org>
Date:	Thu, 30 Jul 2015 12:40:35 +0530
From:	Viresh Kumar <viresh.kumar@...aro.org>
To:	edubezval@...il.com
Cc:	linaro-kernel@...ts.linaro.org, rui.zhang@...el.com,
	linux-pm@...r.kernel.org, radivoje.jovanovic@...ux.intel.com,
	punit.agrawal@....com, Viresh Kumar <viresh.kumar@...aro.org>,
	linux-kernel@...r.kernel.org (open list)
Subject: [PATCH 6/6] thermal/cpu_cooling: update policy limits if clipped_freq < policy->max

policy->max is the maximum allowed frequency defined by user and
clipped_freq is the maximum that thermal constraints allow.

If clipped_freq is lower than policy->max, then we need to readjust
policy->max.

But, if clipped_freq is greater than policy->max, we don't need to do
anything. We used to call cpufreq_verify_within_limits() in this case,
but it doesn't change anything in this case.

Lets skip this unnecessary call and write a comment that explains this.

Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
---
 drivers/thermal/cpu_cooling.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/thermal/cpu_cooling.c b/drivers/thermal/cpu_cooling.c
index 9209c324a7fc..d9a603588cb5 100644
--- a/drivers/thermal/cpu_cooling.c
+++ b/drivers/thermal/cpu_cooling.c
@@ -226,9 +226,20 @@ static int cpufreq_thermal_notifier(struct notifier_block *nb,
 		if (!cpumask_test_cpu(policy->cpu, &cpufreq_dev->allowed_cpus))
 			continue;
 
+		/*
+		 * policy->max is the maximum allowed frequency defined by user
+		 * and clipped_freq is the maximum that thermal constraints
+		 * allow.
+		 *
+		 * If clipped_freq is lower than policy->max, then we need to
+		 * readjust policy->max.
+		 *
+		 * But, if clipped_freq is greater than policy->max, we don't
+		 * need to do anything.
+		 */
 		clipped_freq = cpufreq_dev->clipped_freq;
 
-		if (policy->max != clipped_freq)
+		if (policy->max > clipped_freq)
 			cpufreq_verify_within_limits(policy, 0, clipped_freq);
 		break;
 	}
-- 
2.4.0

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