Manual fan control on iBook G4?

[Justin Hibbits]

On Mon, 28 Jul 2014 22:35:59 +0700
Alexey Dokuchaev <danfe at nsu.ru> wrote:

> Hi there,
> 
> I've digged out that old pity iBook G4 of mine (should be something
> like PowerBook6,5 I guess) that had been hanging under Tiger within
> few minutes after boot and installed FreeBSD on it.  Surprisingly, it
> works fine under it. :)
> 
> I'm suspecting either a faulty harddrive, or non-working fan.  So far
> no matter what heavy port I build, fan does not kick it.  Does
> FreeBSD support fan control on this baby?  How can I manually engage
> it to see if it works? (I've tested that power line has +5V, but
> don't know how can I PWM control it from command line.  Is it PWM, in
> fact? -- just guessing since there are four wires coming into it.)
> 
> Another weird thing: CPU frequency per dmesg(8) is strangely low:
> 
>   $ grep cpu0 /var/run/dmesg.boot
>   cpu0: Motorola PowerPC 7447A revision 1.1, 535.22 MHz
>   cpu0: Features 9c000000<PPC32,ALTIVEC,FPU,MMU>
> 
> while per various websites, 7447A CPU on it should clock at at least
> 1GHz.
> 
> Any clues?  How can I read Mac model from NVRAM (akin to what Mac OS X
> provides via `hw.model' sysctl, or something like that)?  Thanks.
> 
> ./danfe

If you do 'ofwdump -ap', it'll list everything from Open Firmware,
including the fan data (likely i2c-based, look for adm* or adt*).

It's possible the CPU is starting in the reduced clock speed, so you
can check `dev.cpu' syctl to see what levels are supported.

- Justin