Re: [PATCH v1] arm64: dts: sdm845: enable tsens thermal zones

From: Matthias Kaehlcke
Date: Wed Aug 29 2018 - 14:12:20 EST


On Wed, Aug 29, 2018 at 11:39:12AM +0200, Daniel Lezcano wrote:
> On 18/07/2018 09:49, Amit Kucheria wrote:
> > One thermal zone per cpu is defined
>
> The thermal zones are very close, especially when the CPUs belong to the
> same 'cluster'. Very likely the temperature will propagate from one core
> to another core, so when one core reaches the trip0, there is good
> chance the other cores will be close and cross the trip0 threshold too.
>
> Having multiple thermal zones, one per CPU, may trigger an interrupts
> storm with the passive polling timer delay.
>
> Does this board have a cooling device per CPU also ?

The cpufreq driver is still under development:
https://lore.kernel.org/patchwork/patch/966833/ . It currently doesn't
register cooling devices, but since CPUs from a 'cluster' use the same
cpufreq policy I think there will be one cooling device per 'cluster'.