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SubjectRe: [PATCH] drivers: thermal: Reset previous low and high trip during thermal zone init
On 2021-11-05 20:52, Rafael J. Wysocki wrote:
> On Tue, Nov 2, 2021 at 9:01 PM Manaf Meethalavalappu Pallikunhi
> <manafm@codeaurora.org> wrote:
>>
>> During the suspend is in process, thermal_zone_device_update bails out
>> thermal zone re-evaluation for any sensor trip violation without
>> setting next valid trip to that sensor. It assumes during resume
>> it will re-evaluate same thermal zone and update trip. But when it is
>> in suspend temperature goes down and on resume path while updating
>> thermal zone if temperature is less than previously violated trip,
>> thermal zone set trip function evaluates the same previous high and
>> previous low trip as new high and low trip. Since there is no change
>> in high/low trip, it bails out from thermal zone set trip API without
>> setting any trip. It leads to a case where sensor high trip or low
>> trip is disabled forever even though thermal zone has a valid high
>> or low trip.
>>
>> During thermal zone device init, reset thermal zone previous high
>> and low trip. It resolves above mentioned scenario.
>
> Makes sense to me.
>
> Daniel?
>
>> Signed-off-by: Manaf Meethalavalappu Pallikunhi
>> <manafm@codeaurora.org>
>> ---
>> drivers/thermal/thermal_core.c | 2 ++
>> 1 file changed, 2 insertions(+)
>>
>> diff --git a/drivers/thermal/thermal_core.c
>> b/drivers/thermal/thermal_core.c
>> index 21db445..2b7a0b4 100644
>> --- a/drivers/thermal/thermal_core.c
>> +++ b/drivers/thermal/thermal_core.c
>> @@ -477,6 +477,8 @@ static void thermal_zone_device_init(struct
>> thermal_zone_device *tz)
>> {
>> struct thermal_instance *pos;
>> tz->temperature = THERMAL_TEMP_INVALID;
>> + tz->prev_low_trip = -INT_MAX;
>
> Why not use INT_MIN instead?
>
The thermal_zone_set_trips API uses -INT_MAX as default low trip to
start trip aggregation. I used the same default values here as well.

>> + tz->prev_high_trip = INT_MAX;
>> list_for_each_entry(pos, &tz->thermal_instances, tz_node)
>> pos->initialized = false;
>> }
>> --

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