linux-kernel - [PATCH] cpufreq: Avoid calling cpufreq driver's target() routine if target

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Message-Id: <1d7b6e421a335255da956804b43ce3517538409c.1351244153.git.viresh.kumar@linaro.org>
Date:	Fri, 26 Oct 2012 15:06:26 +0530
From:	Viresh Kumar <viresh.kumar@...aro.org>
To:	rjw@...k.pl
Cc:	cpufreq@...r.kernel.org, linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	linaro-dev@...ts.linaro.org, patches@...aro.org,
	pdsw-power-team@....com, Viresh Kumar <viresh.kumar@...aro.org>
Subject: [PATCH] cpufreq: Avoid calling cpufreq driver's target() routine if target_freq == policy->cur

Avoid calling cpufreq driver's target() routine if new frequency is same as
policies current frequency.

Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
---
 drivers/cpufreq/cpufreq.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 261ef65..28dc134 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1476,6 +1476,10 @@ int __cpufreq_driver_target(struct cpufreq_policy *policy,
 
 	pr_debug("target for CPU %u: %u kHz, relation %u\n", policy->cpu,
 		target_freq, relation);
+
+	if (target_freq == policy->cur)
+		return 0;
+
 	if (cpu_online(policy->cpu) && cpufreq_driver->target)
 		retval = cpufreq_driver->target(policy, target_freq, relation);
 
-- 
1.7.12.rc2.18.g61b472e


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