Power Management Timer Support

modulename: acpi_pm.ko

configname: CONFIG_X86_PM_TIMER

Linux Kernel Configuration
└─>Power management and ACPI options
└─>ACPI (Advanced Configuration and Power Interface) Support
└─>Power Management Timer Support
In linux kernel since version 2.6.12  
The Power Management Timer is available on all ACPI-capable,
in most cases even if ACPI is unusable or blacklisted.

This timing source is not affected by power management features
like aggressive processor idling, throttling, frequency and/or
voltage scaling, unlike the commonly used Time Stamp Counter
(TSC) timing source.

You should nearly always say Y here because many modern
systems require this timer.

source code: