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Commit aaac8cab authored by Sai Gurrappadi's avatar Sai Gurrappadi Committed by Greg Kroah-Hartman
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cpufreq: Fix GOV_LIMITS handling for the userspace governor 



commit e43e94c1eda76dabd686ddf6f7825f54d747b310 upstream.

Currently, the userspace governor only updates frequency on GOV_LIMITS
if policy->cur falls outside policy->{min/max}. However, it is also
necessary to update current frequency on GOV_LIMITS to match the user
requested value if it can be achieved within the new policy->{max/min}.

This was previously the behaviour in the governor until commit d1922f02
("cpufreq: Simplify userspace governor") which incorrectly assumed that
policy->cur == user requested frequency via scaling_setspeed. This won't
be true if the user requested frequency falls outside policy->{min/max}.
Ex: a temporary thermal cap throttled the user requested frequency.

Fix this by storing the user requested frequency in a seperate variable.
The governor will then try to achieve this request on every GOV_LIMITS
change.

Fixes: d1922f02 (cpufreq: Simplify userspace governor)
Signed-off-by: default avatarSai Gurrappadi <sgurrappadi@nvidia.com>
Acked-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 73e6305c

drivers/cpufreq/cpufreq_userspace.c

+38 −5
Original line number Original line Diff line number Diff line
@@ -17,6 +17,7 @@ 
#include <linux/init.h>

#include <linux/init.h>

#include <linux/module.h>

#include <linux/module.h>

#include <linux/mutex.h>

#include <linux/mutex.h>

#include <linux/slab.h>





static DEFINE_PER_CPU(unsigned int, cpu_is_managed);

static DEFINE_PER_CPU(unsigned int, cpu_is_managed);

static DEFINE_MUTEX(userspace_mutex);

static DEFINE_MUTEX(userspace_mutex);
@@ -31,6 +32,7 @@ static DEFINE_MUTEX(userspace_mutex); 
static int cpufreq_set(struct cpufreq_policy *policy, unsigned int freq)

static int cpufreq_set(struct cpufreq_policy *policy, unsigned int freq)

{

{

	int ret = -EINVAL;

	int ret = -EINVAL;

	unsigned int *setspeed = policy->governor_data;





	pr_debug("cpufreq_set for cpu %u, freq %u kHz\n", policy->cpu, freq);

	pr_debug("cpufreq_set for cpu %u, freq %u kHz\n", policy->cpu, freq);
@@ -38,6 +40,8 @@ static int cpufreq_set(struct cpufreq_policy *policy, unsigned int freq) 
	if (!per_cpu(cpu_is_managed, policy->cpu))

	if (!per_cpu(cpu_is_managed, policy->cpu))

		goto err;

		goto err;





	*setspeed = freq;



	ret = __cpufreq_driver_target(policy, freq, CPUFREQ_RELATION_L);

	ret = __cpufreq_driver_target(policy, freq, CPUFREQ_RELATION_L);

 err:

 err:

	mutex_unlock(&userspace_mutex);

	mutex_unlock(&userspace_mutex);
@@ -49,19 +53,45 @@ static ssize_t show_speed(struct cpufreq_policy *policy, char *buf) 
	return sprintf(buf, "%u\n", policy->cur);

	return sprintf(buf, "%u\n", policy->cur);

}

}





static int cpufreq_userspace_policy_init(struct cpufreq_policy *policy)

{

	unsigned int *setspeed;



	setspeed = kzalloc(sizeof(*setspeed), GFP_KERNEL);

	if (!setspeed)

		return -ENOMEM;



	policy->governor_data = setspeed;

	return 0;

}



static int cpufreq_governor_userspace(struct cpufreq_policy *policy,

static int cpufreq_governor_userspace(struct cpufreq_policy *policy,

				   unsigned int event)

				   unsigned int event)

{

{

	unsigned int *setspeed = policy->governor_data;

	unsigned int cpu = policy->cpu;

	unsigned int cpu = policy->cpu;

	int rc = 0;

	int rc = 0;





	if (event == CPUFREQ_GOV_POLICY_INIT)

		return cpufreq_userspace_policy_init(policy);



	if (!setspeed)

		return -EINVAL;



	switch (event) {

	switch (event) {

	case CPUFREQ_GOV_POLICY_EXIT:

		mutex_lock(&userspace_mutex);

		policy->governor_data = NULL;

		kfree(setspeed);

		mutex_unlock(&userspace_mutex);

		break;

	case CPUFREQ_GOV_START:

	case CPUFREQ_GOV_START:

		BUG_ON(!policy->cur);

		BUG_ON(!policy->cur);

		pr_debug("started managing cpu %u\n", cpu);

		pr_debug("started managing cpu %u\n", cpu);





		mutex_lock(&userspace_mutex);

		mutex_lock(&userspace_mutex);

		per_cpu(cpu_is_managed, cpu) = 1;

		per_cpu(cpu_is_managed, cpu) = 1;

		*setspeed = policy->cur;

		mutex_unlock(&userspace_mutex);

		mutex_unlock(&userspace_mutex);

		break;

		break;

	case CPUFREQ_GOV_STOP:

	case CPUFREQ_GOV_STOP:
@@ -69,20 +99,23 @@ static int cpufreq_governor_userspace(struct cpufreq_policy *policy, 




		mutex_lock(&userspace_mutex);

		mutex_lock(&userspace_mutex);

		per_cpu(cpu_is_managed, cpu) = 0;

		per_cpu(cpu_is_managed, cpu) = 0;

		*setspeed = 0;

		mutex_unlock(&userspace_mutex);

		mutex_unlock(&userspace_mutex);

		break;

		break;

	case CPUFREQ_GOV_LIMITS:

	case CPUFREQ_GOV_LIMITS:

		mutex_lock(&userspace_mutex);

		mutex_lock(&userspace_mutex);

		pr_debug("limit event for cpu %u: %u - %u kHz, currently %u kHz\n",

		pr_debug("limit event for cpu %u: %u - %u kHz, currently %u kHz, last set to %u kHz\n",

			cpu, policy->min, policy->max,

			cpu, policy->min, policy->max, policy->cur, *setspeed);

			policy->cur);





		if (policy->max < policy->cur)

		if (policy->max < *setspeed)

			__cpufreq_driver_target(policy, policy->max,

			__cpufreq_driver_target(policy, policy->max,

						CPUFREQ_RELATION_H);

						CPUFREQ_RELATION_H);

		else if (policy->min > policy->cur)

		else if (policy->min > *setspeed)

			__cpufreq_driver_target(policy, policy->min,

			__cpufreq_driver_target(policy, policy->min,

						CPUFREQ_RELATION_L);

						CPUFREQ_RELATION_L);

		else

			__cpufreq_driver_target(policy, *setspeed,

						CPUFREQ_RELATION_L);

		mutex_unlock(&userspace_mutex);

		mutex_unlock(&userspace_mutex);

		break;

		break;

	}

	}