Linux Power Management detailed

1. Overview

Although Linux can run on any PC with more than 386 PCs, most people now use a new desktop PC or laptop with a variety of peripherals, and the power management function (PM) is becoming increasingly important. Power management on laptops can save energy and prolong battery life, while on desktop PCs it can reduce radiation, cool down and prolong the service life of peripherals. Most of the operating systems now have power management support, such as Windows and Linux.

The method of realizing power management in 2.PC machine

To achieve power management, the most important thing is two: the first is the need for the device itself to support power-saving functions, such as hard disk, can be temporarily closed through instructions; the second is that the operating system will need to be powered up, so that the power management function can be invoked to turn off the device after a

Two types of power management standards: APM and ACPI

The traditional APM (Advanced power Management) is a BIOS based source management standard, The latest version is 1.2, which provides CPU and device power management features, however, because this type of power management is mainly implemented by the BIOS, there are some drawbacks, such as excessive reliance on the BIOS, incompatibility between the old and new bios, and the inability to determine whether the power management commands were initiated by the user or by the BIOS, for some new 　　Hardware such as USB and 1394 is not supported. To make up for APM's flaws, new power management ACPI came into being, which is ACPI (Advanced and Power Interface), which mainly converts the primary performer of the source management from the BIOS to the operating system, This can provide greater flexibility and scalability.

Currently, PC motherboards typically support both APM and ACPI two standards.