Intel D865PCD Acpi, System States and Power States, Effects of Pressing the Power Switch

Product Description

Power Management Event signal (PME#) wake-up support

1.11.1ACPI

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 D865PCD 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 32)

•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

…and the power switch is

If the system is in this state… pressed for

…the system enters 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)

Less than four seconds

Less than four seconds

More than four seconds

Less than four seconds

More than four seconds

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)

For information about	Refer to
The Desktop Boards’ compliance level with ACPI	Section 1.3, page 16

1.11.1.1System 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 Desktop Board D865PCD and along with the associated system power targets. See the ACPI specification for a complete description of the various system and power states.

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