Specifications

QSSC-S4R Technical Product Specification Operating System Boot, Sleep, and Wake
215
The BIOS supports ACPI 3.0, 2.0 and 1.0b tables. To prevent conflicts with a non-ACPI-aware OS, the memory used
for the ACPI tables is marked as “reserved” in INT 15h, function E820h.
As described in the ACPI specifications, an ACPI-aware OS generates an SMI to request that the system be switched
into the ACPI mode. The BIOS responds by setting up all system-specific (chipset-specific) configurations required to
support ACPI, issuing the appropriate command to the BMC to enable the ACPI mode, and setting the SCI_EN bit as
defined by the ACPI specification. The system automatically returns to the legacy mode on hard reset or power-on
reset.
There are three run-time components to ACPI:
x ACPI Tables
These tables describe the interfaces to the hardware. The ACPI tables can make use of ACPI Machine
Language (AML), the interpretation of which is performed by the OS. The OS contains and uses an AML
interpreter that executes procedures encoded in AML and is stored in the ACPI tables. AML is a compact,
tokenized, abstract machine language. The tables contain information about power management capabilities of
the system, APICs, and bus structure. The tables also describe control methods that the OS uses to change
PCI interrupt routing, control legacy devices in the Super I/O, find out the cause of a wake event, and handle
PCI hot plug, if applicable.
x ACPI Registers
These are the constrained part of the hardware interface, described (at least in location) by the ACPI tables.
x ACPI BIOS
This is the code that boots the machine and implements interfaces for sleep, wake, and some restart
operations. The ACPI description tables are also provided by the ACPI BIOS.
The BIOS supports the following Advanced Configuration and Power Interface Specification, Revision 2.0, and the
Advanced Configuration and Power Interface Specification, Revision 3.0 tables:
Table 145. Supported ACPI Tables
A
CPI
Table
Table
Description
A
CPI
v
2.0
Compliant
A
CPI
v
3.0
Compliant
DSDT Differentiated S
y
stem Description Table
Y
es
Y
es
FADT Fixed ACPI Description Table
Y
es
Y
es
FACS Firmware ACPI Control Structure
Y
es
Y
es
HPET High Precision Event Timer Table No
Y
es
MADT Multiple APIC Description Table
Y
es
Y
es
MCFG Memor
y
Mapped Configuration Space Base Address Description Table No
Y
es
RSDT Root S
y
stem Description Table
Y
es
Y
es
SLIC Software Licensing Description Table No
Y
es
SPCR Serial Port Console Redirection Table
Y
es
Y
es
SSDT Secondary S
y
stem Description Table
Y
es
Y
es
TCPA Trusted Computing Platform Alliance Capabilities Table No
Y
es
SLIT S
y
stem Locality Distance Information Table No
Y
es
SRAT S
y
stem Resource Affinity Table No
Y
es
X
SDT Extended S
y
stem Descriptor Table
Y
es
Y
es
BERT Boot Error Record Table No
Y
es
HEST Hardware Error Source Table No
Y
es
ERST Error Record Serialization Table No
Y
es
DMAR DMA Resource Descriptor Table No
Y
es
The format and location of these tables is documented in the following public documents:
Advanced Configuration and Power Interface Specification, Revision 2.0, July 2000 and Advanced Configuration and
Power Interface Specification
, Revision 3.0.
The ACPI specification requires the system to support at least one sleep state. The BIOS supports S0, S1, and S5
states. S1 is considered a sleep state.
This platform can wake up from the S1 state using the USB devices in addition to the sources described below.