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Some questions about CPU power management


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#1
Liankao

Liankao

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Hello,guys! I am a newbie.I just finished installing OS X 10.9 mavericks and I have some questions that really confuse me.
1.What are the functions of XCPM and AppleIntelCPUPowerManagement.kext?(generating pstates and cstates?enabling sleep?) Is it necessary to make the native CPU power management work?
2.Is using kernelPM the same as using a patched mach_kernel with no XCPM?
3.If the answer to Q2 is yes,for a haswell CPU,can I patch the AICPM.kext to make it work?
Someone pleeeease help me out!thanks!

#2
pokenguyen

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1. Control CPU Power, speedstep, turbo boost, etc. CPU Power can affect other functions like sleep, shutdown.
2. No, KernelPM patches the kernel to prevent kernel panic caused by writing operation to MSR02 register (which is disabled on most BIOS).
3. For haswell, CPU power management is controlled by mach_kernel, AICPM is not used. If you use XCPM free mach_kernel, it will use AICPM to control CPU, then you need to patch AICPM to prevent kernel panic caused by writing operation to MSR02 register (which is disabled on most BIOS).

#3
Liankao

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1. Control CPU Power, speedstep, turbo boost, etc. CPU Power can affect other functions like sleep, shutdown.
2. No, KernelPM patches the kernel to prevent kernel panic caused by writing operation to MSR02 register (which is disabled on most BIOS).
3. For haswell, CPU power management is controlled by mach_kernel, AICPM is not used. If you use XCPM free mach_kernel, it will use AICPM to control CPU, then you need to patch AICPM to prevent kernel panic caused by writing operation to MSR02 register (which is disabled on most BIOS).

Thank you.Now I set kernelPM=true to boot 10.9.How can I know XCPM is working?The AICPM isn‘t loaded, and I can't get my computer to sleep.



#4
pokenguyen

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Thank you.Now I set kernelPM=true to boot 10.9.How can I know XCPM is working?The AICPM isn‘t loaded, and I can't get my computer to sleep.


Check your PStates by DPCI Manager, if it has > 3 steps, your CPU Power Management is working well.

Sleep can be caused by lots of issues, like USB need dsdt patching, usb 3.0 driver, set hibernatemode to 0, and you have to wait for 30s before it really sleeps with Mavericks.





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