Comment 1 for bug 1442423

Agreed in theory. In practice though, the processing units are the main heat sources. There is little reason in having a processing unit fan be driven by the battery temperature sensor, and doing so would undercool the processing unit, which is undesirable.

CPU and GPU die temperatures have been reported to present frequent sudden variations, while CPU and GPU proximity temperatures have smoother variations. This is most likely because the changes in die temperature are lowpass-filtered and delayed by the conductive material between the die and the proximity sensors. That makes TC0P and TG0P better candidates for smoothly driving the CPU and GPU fans than TC0D and TG0D.

However it would be a nice feature to let the user decide which CPU and GPU temperature sensors should be used to drive the fans: perhaps some user would rather use the die temperature, another one the heatsink temperature, and a third one the default proximity temperature. There are, after all, at least two users who reported TC0P not being an accurate assessment of CPU temperature on two recent Macbook Pro (https://github.com/MikaelStrom/macfanctld/issues/10). These users would benefit from such a feature.

I'm upvoting this feature request, with the added requirement that macfanctld should revert back to using TC0P (resp. TG0P, if present) if the user doesn't choose at least one TC?? sensor (resp. one TG?? sensor, if any are present). What do you think?