ACPI（一）基本概念

对于新知识的学习，个人认为要由整体到部分，首先要掌握这是个什么东西？作用是什么？而不是直接研究该技术的内容，今日对ACPI的知识总结如下：

一、ACP规范的目的

ACPI(advanced configuration and power interface)规范定义了标准的工业接口，使OS直接主导主板设备的配置和主板设备及整个系统的电源管理；原Advanced Power Management模型(APM)将电源管理几乎完全分配给BIOS控制，限制了操作系统在控制电能消耗方面的功能。

        The Advanced Configuration and Power Interface (ACPI) specification was  developed to establish industry common interfaces enabling robust operating system (OS)-directed motherboard device configuration and power management of both devices and entire systems. ACPI is the key element in Operating System-directed configuration and Power Management (OSPM).

二、ACPI的内容及架构

ACPI规范定义了硬件接口、软件接口和数据结构，既不是一个软件规范也不是一个硬件规范，ACPI是个包括软件接口、硬件接口的接口规范。

This specification defines ACPI hardware interfaces, ACPI software interfaces and ACPI data structures. This specification also defines the semantics of these interfaces.ACPI is not a software specification; it is not a hardware specification, although it addresses both software and hardware and how they must behave. ACPI is, instead, an interface specification comprised of both software  and hardware elements.

ACPI系统架构如下：

 Figure   1-1 lays out the software and hardwarecomponents relevant to OSPM/ACPI and how they relate to each other（ACPI系统的软硬件组件及他们间的关系）. This  specification describes the interfaces between  components, the contents of the ACPI System Description Tables, and the related semantics of the other ACPI components. Notice that the ACPI System Description Tables,  which describe a particular platform’s hardware, are at heart of the ACPI implementation（ACPI应用的核心是ACPI系统描述表） and the role of the ACPI System Firmware is primarily to supply the ACPI Tables (rather  than a native instruction API).

三、ACPI实现的功能

The functional areas covered by the ACPI specification are:

系统电源管理（System power management）

设备电源管理（Device power management）

处理器电源管理（Processor power management）

设备和处理器性能管理（Device and processor performance management）

配置/即插即用（Configuration/Plug and Play）

系统事件（System Event）

电池管理（Battery management）

温度管理（Thermal management）

嵌入式控制器（Embedded Controller）

SMBus控制器（SMBus Controller）

既然上面提到“ ACPI System Description Tables,  which describe a particular platform’s hardware, are at heart of the ACPI implementation”系统描述表是ACPI规范应用的核心，那下一章将重点介绍系统描述表的概念。