Hello,

> >Stupid question - is this power saving stuff active for G4 CPUs? My iBook
> >doesn't cool down when being idle, it only seems to heats up a little
> >slower than under full load.
> 
> Not for your type of G4:
> 
> from cpu_subr.c
> 
> case MPC7457:
> case MPC7455:
> case MPC7450:
> /* Enable the 7450 branch caches */
>              hid0 |= HID0_SGE | HID0_BTIC;
>              hid0 |= HID0_LRSTK | HID0_FOLD | HID0_BHT;
> /* Disable BTIC on 7450 Rev 2.0 or earlier */
>             if (vers == MPC7450 && (pvr & 0xFFFF) <= 0x0200)
>                    hid0 &= ~HID0_BTIC;
> /* Select NAP mode. */
>            hid0 &= ~(HID0_DOZE | HID0_NAP | HID0_SLEEP);
>            hid0 |= HID0_NAP | HID0_DPM;
>            powersave = 0;/* but don't use it */
> break;
> 
> 
> So when Idle() in locore_subr.S gets to
> 
> #if defined(PPC_OEA)
> /* Check if we can use power saving mode */
>      lis%r8,_C_LABEL(powersave)@ha
>      ldint%r9,_C_LABEL(powersave)@l(%r8)
>      add.%r9,%r9,%r9
>      ble1f
> 
>     sync
>     mfmsr%r4
>    oris%r4,%r4,PSL_POW@h/* enter power saving mode */
>    mtmsr%r4
>    isync
> 
> 1:
> 
> you'll skip setting power saving mode.

Weird - do you have any idea what could be the reason to disable power saving on the 7455? It works nicely with the S900/G3, so I have power saving on the desktop machine but not on the notebook, kind of paradox ;)

have fun
Michael