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SE7500CW2 Server Board Technical Product Specification
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ACPI Tables: These tables describe the interfaces to the hardware. ACPI tables can
make use of a p-code type of language, the interpretation of which is performed by the
OS. The OS contains and uses an AML (ACPI Machine Language) interpreter that
executes procedures encoded in AML and stored in the ACPI tables; ACPI Machine
Language is a compact, tokenized, abstract machine language. The tables contain
information about power management capabilities of the system, APICs, and the bus
structure. The tables also describe control methods that the operating system uses to
change PCI interrupt routing, control legacy devices in Super I/O, and find the cause of
wake events.
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ACPI Registers: ACPI registers are the constrained part of the hardware interface,
described (at least in location) by the ACPI tables.
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ACPI BIOS: This is the code that boots the machine and implements interfaces for
sleep, wake, and some restart operations. The ACPI BIOS also provides the ACPI
Description Tables.
The SE7500CW2 server platform supports S0, S4, and S5 states. The ACPI specification
defines the sleep states and requires the system to support at least one of them.
While entering the S4 state, the operating system saves the context to the disk and most of the
system is powered off. The system can wake from such a state on various inputs depending on
the hardware. Most platforms wake on a power button press, or a signal received from a wake-
on-LAN compliant LAN card (or on-board LAN), modem ring, PCI power management interrupt,
or RTC alarm. The BIOS performs complete POST upon a wake from S4 and it initializes the
platform. The S4 ACPI BIOS state is not supported.
The wake sources are enabled by the ACPI operating systems with co-operation from the
drivers; the BIOS has no direct control over the wake sources when an ACPI OS is loaded. The
role of the BIOS is limited to describing the wake sources to the OS and controlling secondary
control/status bits via a Differentiated System Description Table (DSDT).
The S5 state is equivalent to an OS shutdown. No system context is saved.
6.3.2
Wake Events
The system BIOS is capable of configuring the system to wake up from several sources under a
non-ACPI configuration, such as when the operating system does not support ACPI. The typical
wakes up sources are described in table 5. Under ACPI, the operating system programs the
hardware to wake up on the desired event. The BIOS describes various wake sources to the
operating system.
BIOS always enables the wakeup source, WOL & WOR, in the legacy mode.
Wake Event
Power Button
39
Revision 1.40
Table 11: Supported Wake Events
Support Wake Events
Always wakes system. The Power Botton can be configurable to
different functions under the ACPI mode.
System BIOS
Support Via Legacy
Wake
Always wakes
system
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