linux-kernel - Re: [Patch v5 1/2] ACPI: thermal: Add Thermal fast Sampling Period (

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Date:   Fri, 20 Oct 2023 00:00:53 +0530
From:   Sumit Gupta <sumitg@...dia.com>
To:     "Rafael J. Wysocki" <rafael@...nel.org>
CC:     <rui.zhang@...el.com>, <lenb@...nel.org>,
        <linux-acpi@...r.kernel.org>, <linux-tegra@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <treding@...dia.com>,
        <jonathanh@...dia.com>, <bbasu@...dia.com>, <sanjayc@...dia.com>,
        <ksitaraman@...dia.com>, <srikars@...dia.com>,
        <jbrasen@...dia.com>, Sumit Gupta <sumitg@...dia.com>
Subject: Re: [Patch v5 1/2] ACPI: thermal: Add Thermal fast Sampling Period
 (_TFP) support



On 18/10/23 17:18, Rafael J. Wysocki wrote:
> External email: Use caution opening links or attachments
> 
> 
> On Sat, Oct 14, 2023 at 12:54 PM Sumit Gupta <sumitg@...dia.com> wrote:
>>
>> From: Jeff Brasen <jbrasen@...dia.com>
>>
>> Add support of "Thermal fast Sampling Period (_TFP)" for Passive cooling.
>> As per [1], _TFP overrides the "Thermal Sampling Period (_TSP)" if both
>> are present in a Thermal zone.
>>
>> [1] ACPI Specification 6.4 - section 11.4.17. _TFP (Thermal fast Sampling
>>      Period)"
>>
>> Signed-off-by: Jeff Brasen <jbrasen@...dia.com>
>> Signed-off-by: Sumit Gupta <sumitg@...dia.com>
>> ---
>>   drivers/acpi/thermal.c | 17 +++++++++++------
>>   1 file changed, 11 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/acpi/thermal.c b/drivers/acpi/thermal.c
>> index d98ff69303b3..a91e3d566858 100644
>> --- a/drivers/acpi/thermal.c
>> +++ b/drivers/acpi/thermal.c
>> @@ -90,7 +90,7 @@ struct acpi_thermal_passive {
>>          struct acpi_thermal_trip trip;
>>          unsigned long tc1;
>>          unsigned long tc2;
>> -       unsigned long tsp;
>> +       unsigned long passive_delay;
> 
> This is a passive trip structure anyway, so the "passive_" prefix is
> redundant here.  "delay" alone would be fine.
> 
will change in v6.

>>   };
>>
>>   struct acpi_thermal_active {
>> @@ -404,11 +404,16 @@ static bool passive_trip_params_init(struct acpi_thermal *tz)
>>
>>          tz->trips.passive.tc2 = tmp;
>>
>> -       status = acpi_evaluate_integer(tz->device->handle, "_TSP", NULL, &tmp);
>> -       if (ACPI_FAILURE(status))
>> -               return false;
>> +       status = acpi_evaluate_integer(tz->device->handle, "_TFP", NULL, &tmp);
>> +       if (ACPI_FAILURE(status)) {
>> +               status = acpi_evaluate_integer(tz->device->handle, "_TSP", NULL, &tmp);
>> +               if (ACPI_FAILURE(status))
>> +                       return false;
>>
>> -       tz->trips.passive.tsp = tmp;
>> +               tz->trips.passive.passive_delay = tmp * 100;
>> +       } else {
>> +               tz->trips.passive.passive_delay = tmp;
>> +       }
> 
> I would prefer the if () statement above to be structured the other
> way around, that is
> 
>   status = ...
>   if (ACPI_SUCCESS(status)) {
>          tz->trips.passive.delay = tmp;
>          return true;
> }
> 
> status = ...
> if (ACPI_FAILURE(status))
>           return false;
> 
> etc.
> 

Ok. will change in v6.

>>
>>          return true;
>>   }
>> @@ -904,7 +909,7 @@ static int acpi_thermal_add(struct acpi_device *device)
>>
>>          acpi_trip = &tz->trips.passive.trip;
>>          if (acpi_thermal_trip_valid(acpi_trip)) {
>> -               passive_delay = tz->trips.passive.tsp * 100;
>> +               passive_delay = tz->trips.passive.passive_delay;
>>
>>                  trip->type = THERMAL_TRIP_PASSIVE;
>>                  trip->temperature = acpi_thermal_temp(tz, acpi_trip->temp_dk);
>> --
>> 2.17.1
>>