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Intel Desktop Board D915GVWB Technical Product Specification
1.12.1 ACPI
ACPI gives the operating system direct control over the power management and Plug and Play
functions of a computer. The use of ACPI with this board requires an operating system that
provides full ACPI support. ACPI features include:
•
Plug and Play (including bus and device enumeration)
•
Power management control of individual devices, add-in boards (some add-in boards may
require an ACPI-aware driver), video displays, and hard disk drives
•
Methods for achieving less than 15-watt system operation in the power-on/standby
sleeping state
•
A Soft-off feature that enables the operating system to power-off the computer
•
Support for multiple wake-up events (see Table 9 on page 33)
•
Support for a front panel power and sleep mode switch
Table 7 lists the system states based on how long the power switch is pressed, depending on how
ACPI is configured with an ACPI-aware operating system.
Table 7.
Effects of Pressing the Power Switch
If the system is in this state...
Off
(ACPI G2/G5 – Soft off)
On
(ACPI G0 – working state)
On
(ACPI G0 – working state)
Sleep
(ACPI G1 – sleeping state)
Sleep
(ACPI G1 – sleeping state)
1.12.1.1
System States and Power States
Under ACPI, the operating system directs all system and device power state transitions. The
operating system puts devices in and out of low-power states based on user preferences and
knowledge of how devices are being used by applications. Devices that are not being used can be
turned off. The operating system uses information from applications and user settings to put the
system as a whole into a low-power state.
Table 8 lists the power states supported by the board along with the associated system power targets.
See the ACPI specification for a complete description of the various system and power states.
32
...and the power switch is
pressed for
Less than four seconds
Less than four seconds
More than four seconds
Less than four seconds
More than four seconds
...the system enters this state
Power-on
(ACPI G0 – working state)
Soft-off/Standby
(ACPI G1 – sleeping state)
Fail safe power-off
(ACPI G2/G5 – Soft off)
Wake-up
(ACPI G0 – working state)
Power-off
(ACPI G2/G5 – Soft off)
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