I was pretty disappointed when Chameleon with auto P and C States generation was released and found out that my BIOS had no option to enable HPET. Since I my motherboard (ECS P4M900T-M2) uses VIA chipsets (VT8237S southbridge), Chameleon's trick to force HPET wouldn't work. Because of that AppleCPUPowerManagement panicked if I removed NullCPUPowerManagement.
So I started looking around and found out that linux can force enable HPET on VIA VT8235 and VT8237. I got the source code for the linux kernel and (with a bit of trial and error) adapted the code for VIA HPET forcing for chameleon. I replaced hpet.c with my version (attached) in the Chameleon source code and compiled it (obviously breaks HPET forcing on intel chipsets).
I used a DSDT patcher for a HPET fix as well, so I'm not really sure if the ForceHPET or the DSDT changes are to blame, but now I can remove NullCPUPowerManagement and not get any kernel panics. System profiler shows AppleHPET is loaded and IORegistryExplorer shows a HPET device as well.
If anyone else with a VIA chipset has no option for HPET in their BIOS, they could try this, maybe it works for them too (might need to add device ID in hpet.c for VT8235 or other variations of VT8237). Use at your own risk.
-- Sorry if I posted this in the wrong section.
