On Dec 12, 2004, at 2:31 PM, Tim Kelly wrote:

> At 2:22 PM -0500 12/12/04, Michael wrote:
>> cpu0: HID0 8450c0bc<EMCP,TBEN,NAP,DPM,ICE,DCE,SGE,BTIC,LRSTK,FOLD,BHT>
>> cpu0: 614.39 MHz, 256KB L2 cache
>
> Did the iBooks come with L3 caches? I wonder why the laptops 
> consistently
> get the CPU speed wrong.

	It's a safety feature. OpenFirmware initializes the processor at lower 
than normal clocked speed with the idea that when an operating system 
that can handle talking to the PMU and controlling power and thermal 
management gets loaded that it will kick the processor up to full 
speed. I think there are several reasons for this, battery life, not 
damaging the screen if the system is powered up to OF and the lid is 
closed, etc. I believe the CPU speed scaling feature is specific to the 
750FX but as usual, I'm probably mistaken.

	I think the cooling fan is controlled by logic attached to the PMU. I 
believe it gets the thermal data from the CPU thermal sensor on pre 
uni-north systems via the pmu as well. pmu99 and the uni-n i2c stuff 
isn't too familiar to me. There must be a way to kick the fans onto 
high speed for testing because my Wallstreet does it when you do a PMU 
reset.