Plug and Play BIOS Specification

Plug and Play BIOS Specification 1.0A Page 36
Event Identifier Value Description
ABOUT_TO_CHANGE_CONFIG 0001h This message provides the system with a mechanism whereby
system software can obtain notification from the system BIOS
when a change is about to be made to the system. This
notification encompasses initiating a docking, or undocking,
sequence. For systems that support this message, the docking
sequence will be suspended until the system software issues a
Send_Message() to the system BIOS with either an OK
message indicating that it's OK to dock/undock the system, or an
ABORT message that signals the BIOS to halt the event. (Refer
to Send Message function description below for more
information.)
DOCK_CHANGED 0002h This message indicates that new devices have either been
successfully added or removed from the system, such as docking
to, or undocking from, a docking station. This message will be
used to indicate that a convenience base has been
added/removed from the system.
SYSTEM_DEVICE_CHANGED 0003h This message indicates that removable ("pluggable") system
devices have been removed or inserted into the base unit.
CONFIG_CHANGE_FAILED 0004h This message indicates that the system detected an error when
attempting to add or remove devices to/from the system, such as
attempting to dock to the docking station, or failing to
successfully undock from the docking station. An error code will
be returned in the return status for the Get_Event Plug and Play
BIOS function if the system is able to determine the cause of the
CONFIG_CHANGE_FAILED. Appendix C contains a complete
list of return codes.
UNKNOWN_SYSTEM_EVENT FFFFh An unknown system event has occurred. The system BIOS is not
able to determine the type of event.
OEM_DEFINED_EVENTS 8000h
thru
FFFEh
OEM defined events allow OEM to define events specific to
their system implementation. These events are only
comprehended by the OEM. These events are identified by the
upper bit of the event message being set (bit 7=1).
To properly support event management, a PnP BIOS should implement the PNP_OS_ACTIVE and
PNP_OS_INACTIVE messages, as well as their associated event timing requirements and PnP-OS-Active
states as described in section 4.6.2.