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Commit 8e53695f authored by Viresh Kumar's avatar Viresh Kumar Committed by Rafael J. Wysocki
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cpufreq: governors: Fix WARN_ON() for multi-policy platforms 



On multi-policy systems there is a single instance of governor for both the
policies (if same governor is chosen for both policies). With the code update
from following patches:

8eeed095 cpufreq: governors: Get rid of dbs_data->enable field
b394058f cpufreq: governors: Reset tunables only for cpufreq_unregister_governor()

We are creating/removing sysfs directory of governor for for every call to
GOV_START and STOP. This would fail for multi-policy system as there is a
per-policy call to START/STOP.

This patch reuses the governor->initialized variable to detect total users of
governor.

Signed-off-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 4bd4e428

drivers/cpufreq/cpufreq.c

+4 −2
Original line number Diff line number Diff line
@@ -1552,8 +1552,10 @@ static int __cpufreq_governor(struct cpufreq_policy *policy, 
						policy->cpu, event);

	ret = policy->governor->governor(policy, event);



	if (!policy->governor->initialized && (event == CPUFREQ_GOV_START))

		policy->governor->initialized = 1;

	if (event == CPUFREQ_GOV_START)

		policy->governor->initialized++;

	else if (event == CPUFREQ_GOV_STOP)

		policy->governor->initialized--;



	/* we keep one module reference alive for

			each CPU governed by this CPU */

drivers/cpufreq/cpufreq_governor.c

+19 −13
Original line number Diff line number Diff line
@@ -247,12 +247,14 @@ int cpufreq_governor_dbs(struct dbs_data *dbs_data, 
					     dbs_data->gov_dbs_timer);

		}



		if (!policy->governor->initialized) {

			rc = sysfs_create_group(cpufreq_global_kobject,

					dbs_data->attr_group);

			if (rc) {

				mutex_unlock(&dbs_data->mutex);

				return rc;

			}

		}



		/*

		 * conservative does not implement micro like ondemand
@@ -262,13 +264,15 @@ int cpufreq_governor_dbs(struct dbs_data *dbs_data, 
			cs_dbs_info->down_skip = 0;

			cs_dbs_info->enable = 1;

			cs_dbs_info->requested_freq = policy->cur;



			if (!policy->governor->initialized) {

				cpufreq_register_notifier(cs_ops->notifier_block,

						CPUFREQ_TRANSITION_NOTIFIER);



			if (!policy->governor->initialized)

				dbs_data->min_sampling_rate =

					MIN_SAMPLING_RATE_RATIO *

					jiffies_to_usecs(10);

			}

		} else {

			od_dbs_info->rate_mult = 1;

			od_dbs_info->sample_type = OD_NORMAL_SAMPLE;
@@ -311,11 +315,13 @@ int cpufreq_governor_dbs(struct dbs_data *dbs_data, 
		mutex_lock(&dbs_data->mutex);

		mutex_destroy(&cpu_cdbs->timer_mutex);



		if (policy->governor->initialized == 1) {

			sysfs_remove_group(cpufreq_global_kobject,

					dbs_data->attr_group);

			if (dbs_data->governor == GOV_CONSERVATIVE)

				cpufreq_unregister_notifier(cs_ops->notifier_block,

						CPUFREQ_TRANSITION_NOTIFIER);

		}

		mutex_unlock(&dbs_data->mutex);



		break;