Cannot load p4-clockmod or acpi-cpufreq

Solution Verified - Updated -

Environment

  • Red Hat Enterprise Linux

Issue

I am getting these errors on bootup:

kernel: p4-clockmod: Warning: EST-capable CPU detected. The acpi-cpufreq
module offers voltage scaling in addition of frequency scaling. You 
should use that instead of p4-clockmod, if possible.

After following the instructions outlined here, I am unable to load the acpi-cpufreq module. It fails with the following error:

# modprobe acpi-cpufreq
FATAL: Error inserting acpi_cpufreq (/lib/modules/2.6.32-220.13.1.el6.x86_64/kernel/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.ko): No such device

Resolution

  • Ensure that the system BIOS is configured to allow the OS to control CPU power management.

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