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Re: [PATCH v2 1/5] thermal: change "hysteresis" as optional property

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Hi Leo,

On Fri, Feb 26, 2016 at 11:43:43AM +0800, Leo Yan wrote:
> The property "hysteresis" is mandatory for trip points, so if without
> it the thermal zone cannot register successfully. But "hysteresis" is
> ignored in the thermal subsystem and only inquired by several thermal
> sensor drivers.

I am not sure this a good direction to go. Remember that Linux
implementation not necessarily has to be the implication of the DT
binding. Hysteresis is a property that plays a significant role on
thermal control systems, which in many cases avoid overshooting cooling
actions. Having the DT writer to explicitly set it to 0 means that zone
does not suffer of overshooting and does not need hysteresis.

If the Linux thermal subsystem has a problem with handling hysteresis, I
would rather fix Linux code than relaxing the DT binding. Or if you
still believe hysteresis is really optional, I would prefer to see a
better justification than "Linux ignores it".

BR,

Eduardo

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Thread

[PATCH v2 0/5] thermal: hisilicon: enable power allocator for Hi6220 Leo Yan <leo.yan@linaro.org> - 2016-02-26 04:50 +0100
  [PATCH v2 3/5] thermal: hisilicon: fix IRQ imbalance enabling Leo Yan <leo.yan@linaro.org> - 2016-02-26 04:50 +0100
  [PATCH v2 1/5] thermal: change "hysteresis" as optional property Leo Yan <leo.yan@linaro.org> - 2016-02-26 04:50 +0100
    Re: [PATCH v2 1/5] thermal: change "hysteresis" as optional property Javi Merino <javi.merino@arm.com> - 2016-03-03 11:50 +0100
    Re: [PATCH v2 1/5] thermal: change "hysteresis" as optional property Eduardo Valentin <edubezval@gmail.com> - 2016-03-03 17:30 +0100
      Re: [PATCH v2 1/5] thermal: change "hysteresis" as optional property Leo Yan <leo.yan@linaro.org> - 2016-03-04 04:10 +0100
  [PATCH v2 5/5] arm64: dts: register Hi6220's thermal zone for power allocator Leo Yan <leo.yan@linaro.org> - 2016-02-26 04:50 +0100

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