Compaq 850 manual APM Bios Functions, APM Bios Function Description

Chapter 7 BIOS ROM

Table 7-6. APM BIOS Functions

	Table 7-6.
	APM BIOS Functions
APM BIOS Function	Description
APM Installation Check	Allows the O/S to determine if the system's BIOS
	supports the APM functionality and if so, which version of
	the specification it supports. The APM version number
	returned from this call is the highest level of APM
	supported by the BIOS.
APM Real Mode Interface	Establishes the cooperative interface between the O/S and the
Connect	BIOS. The BIOS provides OEM-defined power management
	functionality before the interface is established. Once the interface
	is established, the BIOS and the O/S Driver coordinate power
	management activities. The BIOS rejects an interface connect
	request if any real or protected mode connection already exists.
APM Protected Mode 16-bit	Initializes the 16-bit protected mode interface between the O/S and
	the BIOS. This interface allows a protected mode caller to invoke
	the BIOS functions without first switching into real or virtual-86
	mode. This function must be invoked in real mode. This is not
	currently used by any O/S.
APM Protected Mode 32-bit	Iinitializes the 32-bit protected mode interface between the O/S and
	the BIOS. This interface allows a protected mode O/S to invoke the
	BIOS functions without the need to first switch into real or virtual-86
	mode. This function must be invoked in real mode.
APM Interface Disconnect	Breaks the cooperative connection between the BIOS and the O/S,
	and returns control of the power management policy to the BIOS.
	Power management parameter values (timer values, enable/disable
	settings, etc.) in effect at the time of the disconnect remain in
	effect.
CPU Idle	The O/S uses this call to tell BIOS that the system is idle.
CPU Busy	Informs the BIOS that the O/S has determined that the system is
	now busy. The BIOS should restore the CPU clock rate to full
	speed.
Set Power State	Sets the system or device specified in the power device ID into the
	requested power state.
Enable/Disable Power	Enables or disables all APM BIOS automatic power management.
Management	When disabled, the BIOS does not automatically power manage
	devices, enter the Standby State, enter the Suspend State, or take
	power saving steps in response to CPU Idle calls.
Restore Power-On Defaults	Re-initializes all power-on defaults.
Get Power Status	This call returns the system current power status.
Get PM Event	Returns the next pending PM event, or indicates if no PM events
	are pending.
Get Power State	Returns the device power state when a specific device ID is used.
Enable/Disable Device PM	Enables or disables APM BIOS automatic power management for a
	specified device. When disabled, the APM BIOS does not
	automatically power manage the device.
APM Driver Version	The O/S uses this call to indicate its level of APM support to the
	BIOS. The BIOS returns the APM connection version number.
Engage/Disengage PM	Engages or disengages cooperative power management of the
	system or device.
Get Capabilities	Returns the features which this particular APM 1.2 BIOS
	implementation supports.
Get/Set/Disable Resume	This call gets, sets, or disables the system resume timer.
Timer
Enable/Disable Resume on	Enables or disables the system's resume on ring indicator
Ring	functionality. It also returns the enabled/disabled status.
Enable/Disable Timer Based	Enables or disables the BIOS's generation of global Standby and
Request	global Suspend requests based on inactivity timers.

7-20Compaq Deskpro EXS and Workstation 300 Personal Computers

Featuring the Intel Pentium 4 Processor

First Edition - December 2000