Programmer’s Guide BCM5722
10/15/07
Broadcom Corporation
Document 5722-PG101-R Advanced Configuration and Power Interface Page 522
ADVANCED CONFIGURATION AND POWER INTERFACE
The Advanced Configuration and Power Interface (ACPI) specification has displaced APM as the power management stan-
dard. APM implements power management in BIOS methods; whereas, ACPI moves power management under the OS um-
brella. ACPI is an interface specification between hardware and software. ACPI outlines mechanisms that both hardware
and software must follow to remain compatible. The ACPI 2.0 specification was written by Intel, Microsoft, Toshiba, Compaq,
and Phoenix Technologies in July 2000.
ACPI can be broken into the following high-level components (see Figure 77):
• OS power management model—The OSPM is responsible for making global decisions regarding power management,
of the system.
• Kernel—The OS Kernel provides the basic Device Driver Interfaces (DDI) and runtime code for objects like
synchronization, resource sharing, and scheduling.
• Power Managed Device Driver—Vendor supplied software, which programs device-specific power management
features. For example, the BCM5722 Ethernet controller needs to disable RX/TX RISC processor clocking for D3 states.
The O/S does not have the necessary runtime code or understanding of the MAC’s architecture.
• ACPI Driver—A O/S subsystem responsible for ACPI power management. The ACPI driver is responsible for
interpreting ACPI Machine Language (AML). AML is typically provided by OEMs for value adds on their platform.
• ACPI Tables—The ACPI tables are descriptions of hardware resources. The interfaces (i.e., registers, memory map),
which ACPI system software may use, are exposed through Definition blocks contained within the ACPI tables. The
ACPI tables also contain AML event handlers for ACPI system events.
• ACPI Registers—The interfaces described in the ACPI Tables.
• ACPI BIOS—The ACPI BIOS contains the ACPI tables, which describe the hardware hierarchy and resources. The
BIOS contains firmware, which boots the PC. Sleep, wake, reset, and event interfaces are contained within the ACPI
BIOS.
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