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Subject[PATCH 1/3] cpufreq: Introduce cpufreq_start_governor()
Date
From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Starting a governor in cpufreq always follows the same pattern
involving two calls to cpufreq_governor(), one with the event
argument set to CPUFREQ_GOV_START and one with that argument set to
CPUFREQ_GOV_LIMITS.

Introduce cpufreq_start_governor() that will carry out those two
operations and make all places where governors are started use it.

That slightly modifies the behavior of cpufreq_set_policy() which
now also will go back to the old governor if the second call to
cpufreq_governor() (the one with event equal to CPUFREQ_GOV_LIMITS)
fails, but that really is how it should work in the first place.

Also cpufreq_resume() will now pring an error message if the
CPUFREQ_GOV_LIMITS call to cpufreq_governor() fails, but that
makes it follow cpufreq_add_policy_cpu() and cpufreq_offline()
in that respect.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
drivers/cpufreq/cpufreq.c | 44 ++++++++++++++++++++++----------------------
1 file changed, 22 insertions(+), 22 deletions(-)

Index: linux-pm/drivers/cpufreq/cpufreq.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/cpufreq.c
+++ linux-pm/drivers/cpufreq/cpufreq.c
@@ -76,6 +76,7 @@ static inline bool has_target(void)
/* internal prototypes */
static int cpufreq_governor(struct cpufreq_policy *policy, unsigned int event);
static unsigned int __cpufreq_get(struct cpufreq_policy *policy);
+static int cpufreq_start_governor(struct cpufreq_policy *policy);

/**
* Two notifier lists: the "policy" list is involved in the
@@ -1015,10 +1016,7 @@ static int cpufreq_add_policy_cpu(struct
cpumask_set_cpu(cpu, policy->cpus);

if (has_target()) {
- ret = cpufreq_governor(policy, CPUFREQ_GOV_START);
- if (!ret)
- ret = cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
-
+ ret = cpufreq_start_governor(policy);
if (ret)
pr_err("%s: Failed to start governor\n", __func__);
}
@@ -1376,10 +1374,7 @@ static void cpufreq_offline(unsigned int
/* Start governor again for active policy */
if (!policy_is_inactive(policy)) {
if (has_target()) {
- ret = cpufreq_governor(policy, CPUFREQ_GOV_START);
- if (!ret)
- ret = cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
-
+ ret = cpufreq_start_governor(policy);
if (ret)
pr_err("%s: Failed to start governor\n", __func__);
}
@@ -1659,9 +1654,7 @@ void cpufreq_resume(void)
policy);
} else {
down_write(&policy->rwsem);
- ret = cpufreq_governor(policy, CPUFREQ_GOV_START);
- if (!ret)
- cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
+ ret = cpufreq_start_governor(policy);
up_write(&policy->rwsem);

if (ret)
@@ -2047,6 +2040,14 @@ static int cpufreq_governor(struct cpufr
return ret;
}

+static int cpufreq_start_governor(struct cpufreq_policy *policy)
+{
+ int ret;
+
+ ret = cpufreq_governor(policy, CPUFREQ_GOV_START);
+ return ret ? ret : cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
+}
+
int cpufreq_register_governor(struct cpufreq_governor *governor)
{
int err;
@@ -2183,8 +2184,10 @@ static int cpufreq_set_policy(struct cpu
return cpufreq_driver->setpolicy(new_policy);
}

- if (new_policy->governor == policy->governor)
- goto out;
+ if (new_policy->governor == policy->governor) {
+ pr_debug("cpufreq: governor limits update\n");
+ return cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
+ }

pr_debug("governor switch\n");

@@ -2212,10 +2215,11 @@ static int cpufreq_set_policy(struct cpu
policy->governor = new_policy->governor;
ret = cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT);
if (!ret) {
- ret = cpufreq_governor(policy, CPUFREQ_GOV_START);
- if (!ret)
- goto out;
-
+ ret = cpufreq_start_governor(policy);
+ if (!ret) {
+ pr_debug("cpufreq: governor change\n");
+ return 0;
+ }
cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
}

@@ -2226,14 +2230,10 @@ static int cpufreq_set_policy(struct cpu
if (cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT))
policy->governor = NULL;
else
- cpufreq_governor(policy, CPUFREQ_GOV_START);
+ cpufreq_start_governor(policy);
}

return ret;
-
- out:
- pr_debug("governor: change or update limits\n");
- return cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
}

/**
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