Re: [PATCH] drivers: thermal: Reset previous low and high trip during thermal zone init

[manafm]

On 2021-11-05 20:52, Rafael J. Wysocki wrote:
> On Tue, Nov 2, 2021 at 9:01 PM Manaf Meethalavalappu Pallikunhi
> <manafm@xxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxx>
> > ---
> >  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;
> >  }
> > --