Acpi; Effects Of Pressing The Power Switch - Intel D845PEBT2 Specification

Intel Desktop Board D845PEBT2 Technical Product Specification

1.16.1 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 the Desktop Board D845PEBT2 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 standby or sleeping state
•
A Soft-off feature that enables the operating system to power-off the computer
•
Support for multiple wake-up events (see Table 8 on page 40)
•
Support for a front panel power and sleep mode switch
Table 6 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 6.

Effects of Pressing the Power Switch

If the system is in this state...
Off
(ACPI S5 – Soft off)
On
(ACPI S0 – working state)
On
(ACPI S0 – working state)
Sleep
(ACPI S1 or S3 – sleeping state)
Sleep
(ACPI S1 or S3 – sleeping state)
For information about
The Desktop Board D845PEBT2's compliance level with ACPI
38
...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 S0 – working state)
Soft-off/Standby
(ACPI S1 or S3 – sleeping state)
Fail safe power-off
(ACPI S5 – Soft off)
Wake-up
(ACPI S0 – working state)
Power-off
(ACPI S5 – Soft off)
Refer to
Section 1.4, page 17