Messages in this thread | | | Date | Mon, 6 Nov 2023 01:02:30 +0100 | Subject | Re: [PATCH v2] thermal: core: Add trip thresholds for trip crossing detection | From | Daniel Lezcano <> |
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Hi Rafael,
On 03/11/2023 15:56, Rafael J. Wysocki wrote: > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > > The trip crossing detection in handle_thermal_trip() does not work > correctly in the cases when a trip point is crossed on the way up and > then the zone temperature stays above its low temperature (that is, its > temperature decreased by its hysteresis). The trip temperature may > be passed by the zone temperature subsequently in that case, even > multiple times, but that does not count as the trip crossing as long as > the zone temperature does not fall below the trip's low temperature or, > in other words, until the trip is crossed on the way down. > > |-----------low--------high------------| > |<--------->| > | hyst | > | | > | -|--> crossed on the way up > | > <---|-- crossed on the way down > > However, handle_thermal_trip() will invoke thermal_notify_tz_trip_up() > every time the trip temperature is passed by the zone temperature on > the way up regardless of whether or not the trip has been crossed on > the way down yet. Moreover, it will not call thermal_notify_tz_trip_down() > if the last zone temperature was between the trip's temperature and its > low temperature, so some "trip crossed on the way down" events may not > be reported. > > To address this issue, introduce trip thresholds equal to either the > temperature of the given trip, or its low temperature, such that if > the trip's threshold is passed by the zone temperature on the way up, > its value will be set to the trip's low temperature and > thermal_notify_tz_trip_up() will be called, and if the trip's threshold > is passed by the zone temperature on the way down, its value will be set > to the trip's temperature (high) and thermal_notify_tz_trip_down() will > be called. Accordingly, if the threshold is passed on the way up, it > cannot be passed on the way up again until its passed on the way down > and if it is passed on the way down, it cannot be passed on the way down > again until it is passed on the way up which guarantees correct > triggering of trip crossing notifications. > > If the last temperature of the zone is invalid, the trip's threshold > will be set depending of the zone's current temperature: If that > temperature is above the trip's temperature, its threshold will be > set to its low temperature or otherwise its threshold will be set to > its (high) temperature. Because the zone temperature is initially > set to invalid and tz->last_temperature is only updated by > update_temperature(), this is sufficient to set the correct initial > threshold values for all trips. > > Link: https://lore.kernel.org/all/20220718145038.1114379-4-daniel.lezcano@linaro.org > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > --- > > v1 (RFC) -> v2: Add missing description of a new struct thermal_trip field. > > And because no comments have been sent for a week, this is not an RFC > any more.
Can you give me a few days to review this patch and test it with some debugfs code planned to be submitted?
Thanks
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