Plug and Play BIOS Specification

Plug and Play BIOS Specification 1.0A Page 51
4.8 Power Management Services
The following subsections describe the Plug and Play support for allowing interaction with Advanced
Power Management (APM) 1.1 and greater.
4.8.1 Function 0Bh - Get APM ID Table
Synopsis:
int FAR (*entryPoint)(Function, Bufsize, ApmIdTable, BiosSelector);
int Function; /* PnP BIOS Function 0Bh */
unsigned int FAR *BufSize; /* Size of buffer to copy APM ID table to */
unsigned char FAR *ApmIdTable; /* Address of caller's buffer for the table */
unsigned int BiosSelector; /* PnP BIOS readable/writable selector */
Description:
Required for Power Management. This function will copy the table of APM 1.1 (or greater) device
identifier to Plug and Play device identifier mappings to the buffer specified by the caller. This allows the
operating system to use the APM interface to perform power management on individual devices controlled
by the system BIOS. If BufSize indicates that the buffer is not large enough to contain the entire table, the
system BIOS will return BUFFER_TOO_SMALL and the size of the buffer required to contain the entire
table will be returned in the caller's BufSize parameter. Therefore, the caller can call this function with
BufSize equal to 0 to determine the size of the buffer it needs to allocate for the APM identifier table. The
apmIDTable argument contains the pointer to the caller's memory buffer. If the buffer is large enough, on
return apmIDTable will contain the APM identifier table. Each entry in the table will be specified in the
following format:
Field Length Value
Device identifier DWORD Varies
APM 1.1 identifier (version 1.1 or greater) WORD Varies
Device Identifier:
This field is the Plug and Play device identifier. The Logical Device ID provides a
mechanism for uniquely identifying multiple logical devices embedded in a single physical
board. The format of the logical device ID is composed of three character compressed ASCII
EISA ID and a manufacturer specific device code.
APM identifier:
This element specifies the corresponding APM device identifier.
An APM identifier table with multiple entries would be described as follows:
Field
Device identifier #1
APM identifier #1
Device identifier #2
APM identifier #2
:
:
Device identifier #n
APM identifier #n
This call supports APM version 1.1 or greater. The APM interface INT 2Fh supports a get version call.
The BiosSelector parameter enables the system BIOS, if necessary, to update system variables that are
contained in the system BIOS memory space. If this function is called from protected mode the caller
must create a data segment descriptor using the 16-bit Protected Mode data segment base address