Comment 1 for bug 1639299

Processor Aggregator Device is introduced on ACPI 4.0 as a mechanism for platforms to ask the OS to force processors to enter (power saving) idle., in order to reduce the platform’s power consumption.

Some description on ACPI spec:
The following section describes the definition and operation of the optional Processor Aggregator
device. The Processor Aggregator Device provides a control point that enables the platform to
perform specific processor configuration and control that applies to all processors in the platform. The Plug and Play ID of the Processor Aggregator Device is ACPI000C.

Acpi_pad driver will do the job for processors to enter idle when platform requests via notification and acpi _PUR methods.
Disable the acpi_pad driver will not put the processors to idle and reduce some power consumption when platform requests.