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

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@vger.kernel.org Reported-by: Hsin-Te Yuan yuanhsinte@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@collabora.com

Reviewed-by: AngeloGioacchino Del Regno angelogioacchino.delregno@collabora.com