ACPI Processor P-States driver

modulename: acpi-cpufreq.ko

configname: CONFIG_X86_ACPI_CPUFREQ

Linux Kernel Configuration
└─>ACPI Processor P-States driver
In linux kernel since version 2.6.12  
This driver adds a CPUFreq driver which utilizes the ACPI
Processor Performance States.
This driver also supports Intel Enhanced Speedstep and newer
AMD CPUs.

To compile this driver as a module, choose M here: the
module will be called acpi-cpufreq.

For details, take a look at Documentation/cpu-freq/.

If in doubt, say N.