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Message-ID: <fcf107da-a164-521d-f507-047b79b1578a@gmail.com>
Date: Fri, 1 Nov 2019 16:56:08 +0300
From: Dmitry Osipenko <digetx@...il.com>
To: Chanwoo Choi <cw00.choi@...sung.com>
Cc: Thierry Reding <thierry.reding@...il.com>,
MyungJoo Ham <myungjoo.ham@...sung.com>,
Kyungmin Park <kyungmin.park@...sung.com>,
Jonathan Hunter <jonathanh@...dia.com>,
Tomeu Vizoso <tomeu.vizoso@...labora.com>,
Peter Geis <pgwipeout@...il.com>, linux-pm@...r.kernel.org,
linux-tegra@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v7 16/19] PM / devfreq: Add new interrupt_driven flag for
governors
01.11.2019 10:32, Chanwoo Choi пишет:
> Hi,
>
> On 19. 10. 30. 오전 7:00, Dmitry Osipenko wrote:
>> Currently interrupt-driven governors (like NVIDIA Tegra30 ACTMON governor)
>> are used to set polling_ms=0 in order to avoid periodic polling of device
>> status by devfreq core. This means that polling interval can't be changed
>> by userspace for such governors.
>>
>> The new governor flag allows interrupt-driven governors to convey that
>> devfreq core shouldn't perform polling of device status and thus generic
>> devfreq polling interval could be supported by these governors now.
>>
>> Signed-off-by: Dmitry Osipenko <digetx@...il.com>
>> ---
>> drivers/devfreq/devfreq.c | 14 +++++++++-----
>> drivers/devfreq/governor.h | 3 +++
>> 2 files changed, 12 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
>> index b905963cea7d..0ef972264841 100644
>> --- a/drivers/devfreq/devfreq.c
>> +++ b/drivers/devfreq/devfreq.c
>> @@ -410,7 +410,8 @@ static void devfreq_monitor(struct work_struct *work)
>> void devfreq_monitor_start(struct devfreq *devfreq)
>> {
>> INIT_DEFERRABLE_WORK(&devfreq->work, devfreq_monitor);
>> - if (devfreq->profile->polling_ms)
>> + if (devfreq->profile->polling_ms &&
>> + !devfreq->governor->interrupt_driven)
>> queue_delayed_work(devfreq_wq, &devfreq->work,
>> msecs_to_jiffies(devfreq->profile->polling_ms));
>> }
>> @@ -474,7 +475,8 @@ void devfreq_monitor_resume(struct devfreq *devfreq)
>> goto out;
>>
>> if (!delayed_work_pending(&devfreq->work) &&
>> - devfreq->profile->polling_ms)
>> + devfreq->profile->polling_ms &&
>> + !devfreq->governor->interrupt_driven)
>
> Better to edit it as following for the indentation.
>
> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
> index cea05b43225f..60c5540b2a55 100644
> --- a/drivers/devfreq/devfreq.c
> +++ b/drivers/devfreq/devfreq.c
> @@ -477,7 +477,7 @@ void devfreq_monitor_resume(struct devfreq *devfreq)
>
> if (!delayed_work_pending(&devfreq->work) &&
> devfreq->profile->polling_ms &&
> - !devfreq->governor->interrupt_driven)
> + !devfreq->governor->interrupt_driven)
>
>
>
>> queue_delayed_work(devfreq_wq, &devfreq->work,
>> msecs_to_jiffies(devfreq->profile->polling_ms));
>>
>> @@ -518,8 +520,9 @@ void devfreq_interval_update(struct devfreq *devfreq, unsigned int *delay)
>>
>> /* if current delay is zero, start polling with new delay */
>> if (!cur_delay) {
>> - queue_delayed_work(devfreq_wq, &devfreq->work,
>> - msecs_to_jiffies(devfreq->profile->polling_ms));
>> + if (!devfreq->governor->interrupt_driven)
>> + queue_delayed_work(devfreq_wq, &devfreq->work,
>> + msecs_to_jiffies(devfreq->profile->polling_ms));
>> goto out;
>> }
>>
>> @@ -528,7 +531,8 @@ void devfreq_interval_update(struct devfreq *devfreq, unsigned int *delay)
>> mutex_unlock(&devfreq->lock);
>> cancel_delayed_work_sync(&devfreq->work);
>> mutex_lock(&devfreq->lock);
>> - if (!devfreq->stop_polling)
>> + if (!devfreq->stop_polling &&
>> + !devfreq->governor->interrupt_driven)
>> queue_delayed_work(devfreq_wq, &devfreq->work,
>> msecs_to_jiffies(devfreq->profile->polling_ms));
>> }
>
> In the devfreq_interval_update(), you better to modify this function as following:
> It is more simple.
>
> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
> index d3d12ed0ed29..80acb55d1686 100644
> --- a/drivers/devfreq/devfreq.c
> +++ b/drivers/devfreq/devfreq.c
> @@ -510,6 +510,9 @@ void devfreq_interval_update(struct devfreq *devfreq, unsigned int *delay)
> if (devfreq->stop_polling)
> goto out;
>
> + if (!devfreq->governor->interrupt_driven)
> + goto out;
> +
> /* if new delay is zero, stop polling */
> if (!new_delay) {
> mutex_unlock(&devfreq->lock);
>
>
>
>> diff --git a/drivers/devfreq/governor.h b/drivers/devfreq/governor.h
>> index bbe5ff9fcecf..dc7533ccc3db 100644
>> --- a/drivers/devfreq/governor.h
>> +++ b/drivers/devfreq/governor.h
>> @@ -31,6 +31,8 @@
>> * @name: Governor's name
>> * @immutable: Immutable flag for governor. If the value is 1,
>> * this govenror is never changeable to other governor.
>> + * @interrupt_driven: Devfreq core won't schedule polling work for this
>> + * governor if value is set to 1.
>> * @get_target_freq: Returns desired operating frequency for the device.
>> * Basically, get_target_freq will run
>> * devfreq_dev_profile.get_dev_status() to get the
>> @@ -49,6 +51,7 @@ struct devfreq_governor {
>>
>> const char name[DEVFREQ_NAME_LEN];
>> const unsigned int immutable;
>> + const unsigned int interrupt_driven;
>> int (*get_target_freq)(struct devfreq *this, unsigned long *freq);
>> int (*event_handler)(struct devfreq *devfreq,
>> unsigned int event, void *data);
>>
>
>
Okay, I'll update this patch.
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