linux-kernel - Re: [PATCH 3/3] thermal/core: Fix thermal trip cross point

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Date:   Fri, 8 Jul 2022 12:48:54 +0200
From:   Daniel Lezcano <daniel.lezcano@...aro.org>
To:     Zhang Rui <rui.zhang@...el.com>, rafael@...nel.org
Cc:     quic_manafm@...cinc.com, Amit Kucheria <amitk@...nel.org>,
        "open list:THERMAL" <linux-pm@...r.kernel.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 3/3] thermal/core: Fix thermal trip cross point

On 08/07/2022 05:56, Zhang Rui wrote:

[ ... ]

>> +	if (tz->last_temperature < trip_temp && tz->temperature >=
>> trip_temp &&
>> +	    trip != tz->prev_trip) {
>> +		thermal_notify_tz_trip_up(tz->id, trip, tz-
>>> temperature);
>> +		tz->prev_trip = trip;
>> +		
>> +	} else if (tz->last_temperature >= trip_low_temp && tz-
>>> temperature < trip_low_temp &&
>> +	    trip == tz->prev_trip) {
>> +		thermal_notify_tz_trip_down(tz->id, trip, tz-
>>> temperature);
>> +		tz->prev_trip = trip - 1;
> 
> Say, let's assume hysteresis is Zero,
> When the temperature increases and we do thermal_notify_tz_trip_up()
> for trip 0 and trip 1, tz->prev_trip is set to 1 in this case.
> And then the temperature drops below trip 0, we don't have chance to do
> thermal_notify_tz_trip_down() for trip 0, because we always handle the
> trips in ascending order, and tz->prev_trip is 1 when we do
> handle_thermal_trip(0).
Well actually you are right, I reproduced the scenario with temperature 
emulation. I'll investigate how to handle this case.

Thanks for spotting this



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