Power management is the process by which the overall consumption of power by a computer is limited based on user requirements and policy. Power management has become a hot topic in the computer world in recent years, as laptops have become more commonplace and users have become more conscious of the environmental and financial effects of limited power resources.
While there is no such thing as perfect power management, since all computers must use some amount of power to run, there have been many advances in system and software architectures to conserve the amount of power being used. Exploiting these features is key to providing good system- and device-level power management.
This paper discusses recent advances in the power management infrastructure of the Linux kernel that will allow Linux to fully exploit the power management capabilities of the various platforms that it runs on. These advances will allow the kernel to provide equally great power management, using a simple interface, regardless of the underlying archtitecture.
This paper covers the two broad areas of power management - System Power Management (SPM) and Device Power Management (DPM). It describes the major concepts behind both subjects and describes the new kernel infrastructure for implementing both. It also discusses the mechanism for implementing hibernation, otherwise known as suspend-to-disk, support for Linux.