Advanced Configuration And Power Interface (Acpi); Sleep And Wake Functionality - Intel SE7520JR2 Technical Manual

Intel® Server Board SE7520JR2 System BIOS
PC200x specifications are intended for systems that are designed to work with Windows 2000*
and Windows XP* class operating systems. The Hardware Design Guide (HDG) for the
Windows XP platform is intended for systems that are designed to work with Windows XP class
operating systems. Each specification classifies the systems further and has requirements
based on the intended usage for that system. For example, a server system that will be used in
small home/office environments has different requirements than one used for enterprise
applications. The BIOS supports HDG 3.0.
4.9.2

Advanced Configuration and Power Interface (ACPI)

The BIOS is ACPI 2.0c compliant. The primary role of the BIOS is to provide ACPI tables.
During POST, the BIOS creates the ACPI tables and locates them in extended memory (above
1MB). The location of these tables is conveyed to the ACPI-aware operating system through a
series of tables located throughout memory. The format and location of these tables is
documented in the publicly available ACPI specification.
To prevent conflicts with a non-ACPI-aware operating system, the memory used for the ACPI
tables is marked as "reserved".
As described in the ACPI specification, an ACPI-aware operating system generates an SMI to
request that the system be switched into ACPI mode. The BIOS responds by setting up all
system (chipset) specific configuration required to support ACPI, and sets the SCI_EN bit as
defined by the ACPI specification. The system automatically returns to legacy mode on hard
reset or power-on reset.
The BIOS supports S0, S1, S4, and S5 states. S1 and S4 are considered sleep 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 on a power button press, or a signal received from
a wake-on-LAN compliant LAN card (or onboard LAN), modem ring, PCI power management
interrupt, or RTC alarm. The BIOS performs complete POST upon wake up from S4, and
initializes the platform.
The system can wake from the S1 state using a PS/2 keyboard, mouse, or USB device, in
addition to the sources described above.
The wake-up sources are enabled by the ACPI operating systems with cooperation from the
drivers; the BIOS has no direct control over the wakeup sources when an ACPI operating
system is loaded. The role of the BIOS is limited to describing the wakeup sources to the
operating system and controlling secondary control/status bits via the DSDT table.
The S5 state is equivalent to operating system shutdown. No system context is saved.
4.9.2.1

Sleep and Wake Functionality

The BIOS supports a control panel power button. The power button is a request that is
forwarded by the mBMC to the ACPI power state machines in the chipset. It is monitored by the
mBMC and does not directly control power on the power supply.
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