Broadcom BCM5722 - Page 577

Programmer’s Guide BCM5722
10/15/07
Broadcom Corporation
Document 5722-PG101-R Reference Materials Page 518
Appendix B: PC Power Management
REFERENCE MATERIALS
The ACPI specification is an industry collaboration between Compaq, Intel
®
, Microsoft
®
, Toshiba
®
, and Phoenix. The fol-
lowing hyperlinks are websites dedicated to the ACPI specification:
• http://developer.intel.com/technology/iapc/acpi/downloads/ACPICA-ProgRef.pdf
• http://www.microsoft.com/hwdev/onnow/
• http://www.toshiba.ca/ISG/newsletter/powermanagement.html
• http://www.phoenix.com/platform/acpi.html
• http://www.teleport.com/~acpi/
The APM specification was authored by Intel and Microsoft. The http://www.microsoft.com/HWDEV/busbios/amp_12.htm
website hyperlink(s) contain more information on APM.
Information regarding PCI power management can be located at the PCI Special Interest Group’s (SIG) website at http://
www.pcisig.com/.
APM
The original Advanced Power Management specification was written in 1992, by Intel and Microsoft. APM is primarily a BIOS
interface and has been outdated by the newer ACPI specification. New servers, workstations, and PCs do not implement
power management using APM.
APM is a four-layer architecture (see Figure 75):
• Layer 1 is the APM BIOS. The system BIOS provides logic for power management of the motherboard. The BIOS is
platform specific software. The APM BIOS may be configured to provide some power management, independent of OS
control. Setup and configuration modes for BIOS normally provide a mechanism to disable independent power
management by BIOS.
• Layer 2 is the APM interface. A common interface, which uses Int15, calls to the APM BIOS. Additional, 16- and 32-bit
protected mode BIOS calls may be published by the BIOS vendor.
• Layer 3 is the OS APM driver. APM aware applications and device drivers interface with the OS APM driver, not the
BIOS directly. The APM driver is responsible for serializing access to the APM BIOS, via the APM interface. The OS
APM driver must call the APM BIOS once per second so the BIOS will not assume a system hang—watchdog type
functionality.
• Layer 4 is the APM aware Device Drivers and applications. NIC vendors like Broadcom provide power management
capable device drivers. Add-in devices, like the BCM5722 Ethernet controller, have a power management capable
device driver.