Advanced Configuration and Power Interface Specification

Advanced Configuration and Power Interface Specification
Table 5-140 ACPI Event Programming Model Components
Component
OSPM
FADT
PM1x_STS and
PM1x_EN fixed
registers
GPEx_STS and
GPEx_EN fixed
registers
SCI interrupt
ACPI AML code
general-purpose event
model
ACPI device-specific
model events
ACPI Embedded
Controller event model
Description
Receives all SCI interrupts raised (receives all SCI events). Either handles the
event or masks the event off and later invokes an OEM-provided control method to
handle the event. Events handled directly by OSPM are fixed ACPI events;
interrupts handled by control methods are general-purpose events.
Specifies the base address for the following fixed register blocks on an ACPIcompatible
platform: PM1x_STS and PM1x_EN fixed registers and the GPEx_STS
and GPEx_EN fixed registers.
PM1x_STS bits raise fixed ACPI events. While a PM1x_STS bit is set, if the
matching PM1x_EN bit is set, the ACPI SCI event is raised.
GPEx_STS bits that raise general-purpose events. For every event bit
implemented in GPEx_STS, there must be a comparable bit in GPEx_EN. Up to
256 GPEx_STS bits and matching GPEx_EN bits can be implemented. While a
GPEx_STS bit is set, if the matching GPEx_EN bit is set, then the general-purpose
SCI event is raised.
A level-sensitive, shareable interrupt mapped to a declared interrupt vector. The
SCI interrupt vector can be shared with other low-priority interrupts that have a low
frequency of occurrence.
A model that allows OEM AML code to use GPEx_STS events. This includes using
GPEx_STS events as “wake” sources as well as other general service events
defined by the OEM (“button pressed,” “thermal event,” “device present/not present
changed,” and so on).
Devices in the ACPI namespace that have ACPI-specific device IDs can provide
additional event model functionality. In particular, the ACPI embedded controller
device provides a generic event model.
A model that allows OEM AML code to use the response from the Embedded
Controller Query command to provide general-service event defined by the OEM.
5.6.2 Types of ACPI Events
At the ACPI hardware level, two types of events can be signaled by an SCI interrupt:
• Fixed ACPI events
• General-purpose events
In turn, the general-purpose events can be used to provide further levels of events to the system.
And, as in the case of the embedded controller, a well-defined second-level event dispatching is
defined to make a third type of typical ACPI event. For the flexibility common in today’s designs,
two first-level general-purpose event blocks are defined, and the embedded controller construct
allows a large number of embedded controller second-level event-dispatching tables to be supported.
Then if needed, the OEM can also build additional levels of event dispatching by using AML code
on a general-purpose event to sub-dispatch in an OEM defined manner.
242 April, 2015 Version 6.0