3-26

Chapter 3

 

 

of a computer. The BIOS is fully support the ACPI functions. If you want ACPI functions to work normally, you should notice two things. One is your operating system must support ACPI, as of now only Microsoft® Windows® 2000, Windows® ME and Windows® XP supports these functions. The second thing is that all devices and add-on cards in your system must fully support ACPI, both hardware and software (drivers). If you want to know if your devices or add-on cards support ACPI or not, please contact the device or add-on card manufacture for more information. If you want to know more about ACPI specifications, please go to the address below for more detailed information:

http://www.teleport.com/~acpi/acpihtml/home.htm

ACPI requires an ACPI-aware operating system. ACPI features include:

!Plug and Play (including bus and device enumeration) and APM functionality normally contained in the BIOS.

!Power management control of individual devices, add-in cards (some add-in cards may require an ACPI-aware driver), video displays, and hard disk drives.

!A Soft-off feature that enables the operating system to power off the computer.

!Support for multiple wake-up events (see Table 3-6-1).

!Support for a front panel power and sleep mode switch. Table 3-6-2 describes the system states based on how long the power switch is pressed, depending on how ACPI is configured with an ACPI-aware operating system.

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.

The table below describes which devices or specific events can wake the computer from specific states.

 

 

Table 3-6-1: Wake Up Device and Events

 

 

 

 

 

 

 

 

These device/events can wake up the computer

 

 

 

 

 

 

 

from this state

 

 

 

Power switch

 

 

Sleeping mode or power off mode

 

 

RTC alarm

 

 

Sleeping mode or power off mode

 

 

PCI Card (PME)

 

 

Sleeping mode or power off mode

 

 

Modem

 

 

Sleeping mode or power off mode

 

 

USB

 

 

Sleeping mode

 

 

 

 

 

 

 

 

 

 

 

Table 3-6-2: Effect of Pressing the Power Switch

 

 

 

 

 

 

 

 

If the system is in this

 

……and the power switch is

……the system enters this

 

 

state……

 

pressed for

state

 

 

Off

 

Less than four seconds

Power on

 

 

On

 

More than four seconds

Soft off/Suspend

 

 

On

 

Less than four seconds

Fail safe power off

 

 

Sleep

 

Less than four seconds

Wake up

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ACPI Suspend Type:

Two options are available: S1 (POS) ( S3 (STR). The default setting is S1 (POS). POS is “Power On

AT7/AT7E