Hello,

> >I only see the 7455s differ in flag - pfCanNap vs. pfWillNap vs nothing,
> >the 7400 and the G3 has pfCanDoze and pfCanNap. So it's clear why the 745x
> >are excluded - no doze mode. But the 7455 v2.1 and the 7457 should be
> >included for nap mode.
> 
> According to MPC7455 User's Manual, the bit defined as HID_DOZE  in
> arch/powerpc/include/oea/hid.h is not DOZE mode for this family. It is
> HIGH_BAT_ENABLE, for additional address space mapping. This gets turned off
> on cpu_subr.c
> 
> /* Select NAP mode. */
> hid0 &= ~(HID0_DOZE | HID0_NAP | HID0_SLEEP);
> hid0 |= HID0_NAP | HID0_DPM;

I enabled powersave on the iBook ( a 7455 v3.3 so Darwin would use nap ) - no negative side-effects so far and the machine indeed seems to cool down. Slowly, but it does.

have fun
Michael