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Message-id: <5B639BD2.5050008@samsung.com>
Date:   Fri, 03 Aug 2018 09:03:30 +0900
From:   Chanwoo Choi <cw00.choi@samsung.com>
Organization: Samsung Electronics
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To:     Matthias Kaehlcke <mka@chromium.org>,
        MyungJoo Ham <myungjoo.ham@samsung.com>
Cc:     Kyungmin Park <kyungmin.park@samsung.com>,
        Arnd Bergmann <arnd@arndb.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>, linux-pm@vger.kernel.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        Brian Norris <briannorris@chromium.org>,
        Douglas Anderson <dianders@chromium.org>,
        Enric Balletbo i Serra <enric.balletbo@collabora.com>,
        "Rafael J . Wysocki" <rjw@rjwysocki.net>,
        Viresh Kumar <viresh.kumar@linaro.org>,
        Lee Jones <lee.jones@linaro.org>,
        Benson Leung <bleung@chromium.org>,
        Olof Johansson <olof@lixom.net>
Subject: Re: [PATCH v5 03/12] PM / devfreq: Don't adjust to user limits in
 governors
In-reply-to: <20180802233600.GT68975@google.com>
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References: <20180703234705.227473-1-mka@chromium.org>
        <20180703234705.227473-4-mka@chromium.org>
        <CGME20180802233605epcas2p2fc6b1cef0dc773f6c7e59017721917bc@epcas2p2.samsung.com>
        <20180802233600.GT68975@google.com>
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Hi Matthias,

On 2018년 08월 03일 08:36, Matthias Kaehlcke wrote:
> Hi Chanwoo,
> 
> this patch and "PM / devfreq: Fix handling of min/max_freq == 0"
> address issues not directly related with the throttler. It seems it
> could still take a while for the throttler to move forward, do you
> want me to spin out these two patches so that they can get merged
> independently from the rest of the series?

How about resend the devfreq patches(patch1/2/3/4/6) which don't depend on
throttler core with my reviewed tag? Maybe, it is easy to merge them through Myungjoo.

Regards,
Chanwoo Choi

> 
> Thanks
> 
> Matthias
> 
> On Tue, Jul 03, 2018 at 04:46:56PM -0700, Matthias Kaehlcke wrote:
>> Several governors use the user space limits df->min/max_freq to adjust
>> the target frequency. This is not necessary, since update_devfreq()
>> already takes care of this. Instead the governor can request the available
>> min/max frequency by setting the target frequency to DEVFREQ_MIN/MAX_FREQ
>> and let update_devfreq() take care of any adjustments.
>>
>> Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
>> Reviewed-by: Brian Norris <briannorris@chromium.org>
>> ---
>> Changes in v5:
>> - none
>>
>> Changes in v4:
>> - added 'Reviewed-by: Brian Norris <briannorris@chromium.org>' tag
>>
>> Changes in v3:
>> - none
>>
>> Changes in v2:
>> - squashed "PM / devfreq: Remove redundant frequency adjustment from governors"
>>   and "PM / devfreq: governors: Return device frequency limits instead of user
>>   limits"
>> - updated subject and commit message
>> - use DEVFREQ_MIN/MAX_FREQ instead of df->scaling_min/max_freq
>> ---
>>  drivers/devfreq/governor.h                |  3 +++
>>  drivers/devfreq/governor_performance.c    |  5 +----
>>  drivers/devfreq/governor_powersave.c      |  2 +-
>>  drivers/devfreq/governor_simpleondemand.c | 12 +++---------
>>  drivers/devfreq/governor_userspace.c      | 16 ++++------------
>>  5 files changed, 12 insertions(+), 26 deletions(-)
>>
>> diff --git a/drivers/devfreq/governor.h b/drivers/devfreq/governor.h
>> index cfc50a61a90d..b81700244ce3 100644
>> --- a/drivers/devfreq/governor.h
>> +++ b/drivers/devfreq/governor.h
>> @@ -25,6 +25,9 @@
>>  #define DEVFREQ_GOV_SUSPEND			0x4
>>  #define DEVFREQ_GOV_RESUME			0x5
>>  
>> +#define DEVFREQ_MIN_FREQ			0
>> +#define DEVFREQ_MAX_FREQ			ULONG_MAX
>> +
>>  /**
>>   * struct devfreq_governor - Devfreq policy governor
>>   * @node:		list node - contains registered devfreq governors
>> diff --git a/drivers/devfreq/governor_performance.c b/drivers/devfreq/governor_performance.c
>> index 4d23ecfbd948..ded429fd51be 100644
>> --- a/drivers/devfreq/governor_performance.c
>> +++ b/drivers/devfreq/governor_performance.c
>> @@ -20,10 +20,7 @@ static int devfreq_performance_func(struct devfreq *df,
>>  	 * target callback should be able to get floor value as
>>  	 * said in devfreq.h
>>  	 */
>> -	if (!df->max_freq)
>> -		*freq = UINT_MAX;
>> -	else
>> -		*freq = df->max_freq;
>> +	*freq = DEVFREQ_MAX_FREQ;
>>  	return 0;
>>  }
>>  
>> diff --git a/drivers/devfreq/governor_powersave.c b/drivers/devfreq/governor_powersave.c
>> index 0c42f23249ef..9e8897f5ac42 100644
>> --- a/drivers/devfreq/governor_powersave.c
>> +++ b/drivers/devfreq/governor_powersave.c
>> @@ -20,7 +20,7 @@ static int devfreq_powersave_func(struct devfreq *df,
>>  	 * target callback should be able to get ceiling value as
>>  	 * said in devfreq.h
>>  	 */
>> -	*freq = df->min_freq;
>> +	*freq = DEVFREQ_MIN_FREQ;
>>  	return 0;
>>  }
>>  
>> diff --git a/drivers/devfreq/governor_simpleondemand.c b/drivers/devfreq/governor_simpleondemand.c
>> index 28e0f2de7100..c0417f0e081e 100644
>> --- a/drivers/devfreq/governor_simpleondemand.c
>> +++ b/drivers/devfreq/governor_simpleondemand.c
>> @@ -27,7 +27,6 @@ static int devfreq_simple_ondemand_func(struct devfreq *df,
>>  	unsigned int dfso_upthreshold = DFSO_UPTHRESHOLD;
>>  	unsigned int dfso_downdifferential = DFSO_DOWNDIFFERENCTIAL;
>>  	struct devfreq_simple_ondemand_data *data = df->data;
>> -	unsigned long max = (df->max_freq) ? df->max_freq : UINT_MAX;
>>  
>>  	err = devfreq_update_stats(df);
>>  	if (err)
>> @@ -47,7 +46,7 @@ static int devfreq_simple_ondemand_func(struct devfreq *df,
>>  
>>  	/* Assume MAX if it is going to be divided by zero */
>>  	if (stat->total_time == 0) {
>> -		*freq = max;
>> +		*freq = DEVFREQ_MAX_FREQ;
>>  		return 0;
>>  	}
>>  
>> @@ -60,13 +59,13 @@ static int devfreq_simple_ondemand_func(struct devfreq *df,
>>  	/* Set MAX if it's busy enough */
>>  	if (stat->busy_time * 100 >
>>  	    stat->total_time * dfso_upthreshold) {
>> -		*freq = max;
>> +		*freq = DEVFREQ_MAX_FREQ;
>>  		return 0;
>>  	}
>>  
>>  	/* Set MAX if we do not know the initial frequency */
>>  	if (stat->current_frequency == 0) {
>> -		*freq = max;
>> +		*freq = DEVFREQ_MAX_FREQ;
>>  		return 0;
>>  	}
>>  
>> @@ -85,11 +84,6 @@ static int devfreq_simple_ondemand_func(struct devfreq *df,
>>  	b = div_u64(b, (dfso_upthreshold - dfso_downdifferential / 2));
>>  	*freq = (unsigned long) b;
>>  
>> -	if (df->min_freq && *freq < df->min_freq)
>> -		*freq = df->min_freq;
>> -	if (df->max_freq && *freq > df->max_freq)
>> -		*freq = df->max_freq;
>> -
>>  	return 0;
>>  }
>>  
>> diff --git a/drivers/devfreq/governor_userspace.c b/drivers/devfreq/governor_userspace.c
>> index 080607c3f34d..378d84c011df 100644
>> --- a/drivers/devfreq/governor_userspace.c
>> +++ b/drivers/devfreq/governor_userspace.c
>> @@ -26,19 +26,11 @@ static int devfreq_userspace_func(struct devfreq *df, unsigned long *freq)
>>  {
>>  	struct userspace_data *data = df->data;
>>  
>> -	if (data->valid) {
>> -		unsigned long adjusted_freq = data->user_frequency;
>> -
>> -		if (df->max_freq && adjusted_freq > df->max_freq)
>> -			adjusted_freq = df->max_freq;
>> -
>> -		if (df->min_freq && adjusted_freq < df->min_freq)
>> -			adjusted_freq = df->min_freq;
>> -
>> -		*freq = adjusted_freq;
>> -	} else {
>> +	if (data->valid)
>> +		*freq = data->user_frequency;
>> +	else
>>  		*freq = df->previous_freq; /* No user freq specified yet */
>> -	}
>> +
>>  	return 0;
>>  }
>>  
> 
>