[PATCH 2/5] thermal/drivers/mediatek/lvts: Disable Stage 3 thermal threshold

[AngeloGioacchino Del Regno]

Il 25/11/24 22:20, Nícolas F. R. A. Prado ha scritto:
> The Stage 3 thermal threshold is currently configured during
> the controller initialization to 105 Celsius. From the kernel
> perspective, this configuration is harmful because:
> * The stage 3 interrupt that gets triggered when the threshold is
>    crossed is not handled in any way by the IRQ handler, it just gets
>    cleared. Besides, the temperature used for stage 3 comes from the
>    sensors, and the critical thermal trip points described in the
>    Devicetree will already cause a shutdown when crossed (at a lower
>    temperature, of 100 Celsius, for all SoCs currently using this
>    driver).
> * The only effect of crossing the stage 3 threshold that has been
>    observed is that it causes the machine to no longer be able to enter
>    suspend. Even if that was a result of a momentary glitch in the
>    temperature reading of a sensor (as has been observed on the
>    MT8192-based Chromebooks).
> 
> For those reasons, disable the Stage 3 thermal threshold configuration.
> 
> Cc: stable at vger.kernel.org
> Reported-by: Hsin-Te Yuan <yuanhsinte at chromium.org>
> Closes: https://lore.kernel.org/all/20241108-lvts-v1-1-eee339c6ca20@chromium.org/
> Fixes: f5f633b18234 ("thermal/drivers/mediatek: Add the Low Voltage Thermal Sensor driver")
> Signed-off-by: Nícolas F. R. A. Prado <nfraprado at collabora.com>

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno at collabora.com>