Tim Kelly <hockey@dialectronics.com> writes:

> >But this reminds me of something else - NetBSD can measure the temperature
> >of the G3 in my S900 but not of the G4 in my iBook - is there no thermal
> >sensor in a G4? Or is the interface different?
> 
> 
> There's a note in powerpc/oea/cpu_subr.c
> 
> #if NSYSMON_ENVSYS > 0
> /*
>  * Attach MPC750 temperature sensor to the envsys subsystem.
>  * XXX the 74xx series also has this sensor, but it is not
>  * XXX supported by Motorola and may return values that are off by
>  * XXX 35-55 degrees C.
>  */
> if (vers == MPC750 || vers == IBM750FX)
>       cpu_tau_setup(ci);
> #endif

That's my doing. The 74xx series manuals are pretty clear that the
temperature sensor on the chip is not supported or even expected to
work.

That said, Apple laptops have more thermal sensors than the one on the
CPU, so finding them (probably i2c devices with OFW entries somewhere)
and adding them to envsys would be a nice little project.

        - Nathan