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Commit 9c41437c authored by Rama Aparna Mallavarapu's avatar Rama Aparna Mallavarapu
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PM/devfreq: Do not switch governors from sysfs when device is suspended 



There is a possibility to switch the governors from sysfs even when the
device is in suspended state. This can cause a NOC error at times when
trying to access the device's monitor registers in a suspended state. This
change fixes this issue. Introduce a variable dev_suspended to know if
the device is in suspended state or not. Check if the device is suspended
before switching the governor from sysfs.

Change-Id: I15055aa51daa35272be4667e5bafb8ccd7933098
Signed-off-by: default avatarRama Aparna Mallavarapu <aparnam@codeaurora.org>
parent 8bf200e7

drivers/devfreq/devfreq.c

+17 −4
Original line number Diff line number Diff line
@@ -596,6 +596,7 @@ struct devfreq *devfreq_add_device(struct device *dev, 
	devfreq->last_status.current_frequency = profile->initial_freq;

	devfreq->data = data;

	devfreq->nb.notifier_call = devfreq_notifier_call;

	devfreq->dev_suspended = false;



	if (!devfreq->profile->max_state && !devfreq->profile->freq_table) {

		mutex_unlock(&devfreq->lock);
@@ -822,12 +823,16 @@ int devfreq_suspend_device(struct devfreq *devfreq) 
	if (!devfreq)

		return -EINVAL;



	if (!devfreq->governor)

	mutex_lock(&devfreq->event_lock);

	if (!devfreq->governor || devfreq->dev_suspended) {

		mutex_unlock(&devfreq->event_lock);

		return 0;

	}



	mutex_lock(&devfreq->event_lock);

	ret = devfreq->governor->event_handler(devfreq,

				DEVFREQ_GOV_SUSPEND, NULL);

	if (!ret)

		devfreq->dev_suspended = true;

	mutex_unlock(&devfreq->event_lock);

	return ret;

}
@@ -847,12 +852,16 @@ int devfreq_resume_device(struct devfreq *devfreq) 
	if (!devfreq)

		return -EINVAL;



	if (!devfreq->governor)

	mutex_lock(&devfreq->event_lock);

	if (!devfreq->governor) {

		mutex_unlock(&devfreq->event_lock);

		return 0;

	}



	mutex_lock(&devfreq->event_lock);

	ret = devfreq->governor->event_handler(devfreq,

				DEVFREQ_GOV_RESUME, NULL);

	if (!ret)

		devfreq->dev_suspended = false;

	mutex_unlock(&devfreq->event_lock);

	return ret;

}
@@ -1015,6 +1024,10 @@ static ssize_t governor_store(struct device *dev, struct device_attribute *attr, 
	}



	mutex_lock(&df->event_lock);

	if (df->dev_suspended) {

		ret = -EINVAL;

		goto gov_stop_out;

	}

	if (df->governor) {

		ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);

		if (ret) {

include/linux/devfreq.h

+1 −0
Original line number Diff line number Diff line
@@ -175,6 +175,7 @@ struct devfreq { 
	unsigned long last_stat_updated;



	struct srcu_notifier_head transition_notifier_list;

	bool dev_suspended;

};



struct devfreq_freqs {