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CPU Cx states with the Intel Celeron (Merom-L)


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I'm in process of "OS X post-install fixing" old Toshiba Satellite L40-17T laptop equipped with Intel Celeron 540 CPU. This CPU is a single core device running at 1.86GHz based on the Core 2 architecture. Unfortunately this CPU lacks support of the Intel SpeedStep technology so no P-states are being supported. Situation is better with the C-states - this CPU supports C0, C2 and C3 halt states, which are successfully found and used by any recent linux distro.


What I want is to force Mac OS X into using C-states as well.


I use AnVAL 5.0.6 as a bootloader and it reports that ACPI tables were successfully patched to support C-states if I add GenerateCStates=Yes to the com.apple.Boot.plist. But I doubt if the states are really used by Mac OS X.


As far as my understanding of the C-states vs. OS function is correct there should be some kind of a driver on the OS side that should replace default idle sleep function with a smarter one that would switch CPU to the C-state sleep. Looks like that in case of vanilla Mac OS X this driver is the famous AppleIntelCPUPowerManagement.kext. Trouble is that I have to blacklist this kext because the Celeron 540 CPU is not officially supported by this driver and causes the kernel panic. It is obvious that I should find some kind of replacement for AICPM.kext and the most obvious candidate for the replacement are Kexts from the VoodooPower* family.


I doubt if VoodooPower*-family Kexts are suitable for enabling C-states on SpeedStep-uncapable systems. Does anybody know if it would work? And are there any ways to check if the Mac OS X system had detected and successfully using CPU C-states (something similar to the /proc/acpi/ interface in linux)?

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