Re: [PATCH v2 3/5] devfreq: add devfreq_suspend/resume() functions

From: Lukasz Luba
Date: Tue Dec 04 2018 - 04:44:57 EST


Hi Chanwoo,

On 12/4/18 7:19 AM, Chanwoo Choi wrote:
> Hi Lukasz,
>
> On 2018ë 12ì 03ì 23:31, Lukasz Luba wrote:
>> This patch adds implementation for global suspend/resume for
>> devfreq framework. System suspend will next use these functions.
>>
>> The patch is based on earlier work by Tobias Jakobi.
>
> Please remove it from each patch description.
OK
>
>>
>> Suggested-by: Tobias Jakobi <tjakobi@xxxxxxxxxxxxxxxxxxxxx>
>> Suggested-by: Chanwoo Choi <cw00.choi@xxxxxxxxxxx>
>> Signed-off-by: Lukasz Luba <l.luba@xxxxxxxxxxxxxxxxxxx>
>> ---
>> drivers/devfreq/devfreq.c | 42 ++++++++++++++++++++++++++++++++++++++++++
>> include/linux/devfreq.h | 6 ++++++
>> 2 files changed, 48 insertions(+)
>>
>> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
>> index 36bed24..7d60423 100644
>> --- a/drivers/devfreq/devfreq.c
>> +++ b/drivers/devfreq/devfreq.c
>> @@ -935,6 +935,48 @@ int devfreq_resume_device(struct devfreq *devfreq)
>> EXPORT_SYMBOL(devfreq_resume_device);
>>
>> /**
>> + * devfreq_suspend() - Suspend devfreq governors and devices
>> + *
>> + * Called during system wide Suspend/Hibernate cycles for suspending governors
>> + * and devices preserving the state for resume. On some platforms the devfreq
>> + * device must have precise state (frequency) after resume in order to provide
>> + * fully operating setup.
>> + */
>> +void devfreq_suspend(void)
>> +{
>> + struct devfreq *devfreq;
>> + int ret;
>> +
>> + mutex_lock(&devfreq_list_lock);
>> + list_for_each_entry(devfreq, &devfreq_list, node) {
>> + ret = devfreq_suspend_device(devfreq);
>> + if (ret)
>> + dev_warn(&devfreq->dev, "device suspend failed\n");
>
> When I checked the cpufreq_suspend(), cpufreq_suspend() prints message as 'err' level.
> I think that dev_err is more proper than dev_warn.
>
> I'm not sure what is more correct log.
> But, 'devfreq->dev' device has the separate suspend/resume function.
> So, I think that devfreq_suspend() should print error log containing
> that it is error by devfreq framework.
>
> "device suspend failed"
> -> "failed to suspend devfreq device"
OK, changed in next v3 patch set.
>
>> + }
>> + mutex_unlock(&devfreq_list_lock);
>> +}
>> +
>> +/**
>> + * devfreq_resume() - Resume devfreq governors and devices
>> + *
>> + * Called during system wide Suspend/Hibernate cycle for resuming governors and
>> + * devices that are suspended with devfreq_suspend().
>> + */
>> +void devfreq_resume(void)
>> +{
>> + struct devfreq *devfreq;
>> + int ret;
>> +
>> + mutex_lock(&devfreq_list_lock);
>> + list_for_each_entry(devfreq, &devfreq_list, node) {
>> + ret = devfreq_resume_device(devfreq);
>> + if (ret)
>> + dev_warn(&devfreq->dev, "device resume failed\n");
>
> ditto.
>
> "device resume failed"
> -> "failed to resume devfreq device"
>
ACK

Regards,
Lukasz
>
>> + }
>> + mutex_unlock(&devfreq_list_lock);
>> +}
>> +
>> +/**
>> * devfreq_add_governor() - Add devfreq governor
>> * @governor: the devfreq governor to be added
>> */
>> diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
>> index d985199..fbffa74 100644
>> --- a/include/linux/devfreq.h
>> +++ b/include/linux/devfreq.h
>> @@ -205,6 +205,9 @@ extern void devm_devfreq_remove_device(struct device *dev,
>> extern int devfreq_suspend_device(struct devfreq *devfreq);
>> extern int devfreq_resume_device(struct devfreq *devfreq);
>>
>> +extern void devfreq_suspend(void);
>> +extern void devfreq_resume(void);
>> +
>> /**
>> * update_devfreq() - Reevaluate the device and configure frequency
>> * @devfreq: the devfreq device
>> @@ -331,6 +334,9 @@ static inline int devfreq_resume_device(struct devfreq *devfreq)
>> return 0;
>> }
>>
>> +static inline void devfreq_suspend(void) {}
>> +static inline void devfreq_resume(void) {}
>> +
>> static inline struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
>> unsigned long *freq, u32 flags)
>> {
>>
>