Introducing the BIOS

 

 

3-25

 

 

 

 

 

 

 

 

 

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

 

 

 

 

 

 

 

 

If the system is in this

 

……and the power switch is

 

 

 

state……

 

pressed for

……the system enters this

 

 

 

 

 

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 (PowerOn-Suspend) ) S3 (Suspend-To-RAM). The default setting is S1

(PowerOn-Suspend). Generally, ACPI has six states: System S0 state, S1 state, S2 state, S3 state, S4 state,

S5 state. S1 and S3 states are described below:

The S1 (POS) State (POS means Power On Suspend):

While the system is in the S1 sleeping state, its behavior is as described below:

!The processor is not executing instructions. The processor’s complex context is maintained.

!Dynamic RAM context is maintained.

!Power Resources are in a state compatible with the system S1 state. All Power Resources that supply a System Level reference of S0 are in the OFF state.

!Devices states are compatible with the current Power Resource states. Only devices which solely reference Power Resources which are in the ON state for a given device state can be in that device state. In all other cases, the device is in the D3 (off) state.

!Devices that are enabled to wake the system and that can do so from their current device state can initiate a hardware event which transitions the system state to S0. This transition causes the processor to continue execution where it left off.

To transition into the S1 state, the operating software does not have to flush the processor's cache.

The S3 (STR) State (STR means Suspend to RAM):

The S3 state is logically lower then the S2 state and is assumed to conserve more power. The behavior of this state is defined as follows:

!Processor is not executing instructions. The processor complex context is not maintained.

!Dynamic RAM context is maintained.

!Power Resources are in a state compatible with the system S3 state. All Power Resources that supply a System Level reference of S0, S1, or S2 are in the OFF state.

!Devices states are compatible with the current Power Resource states. Only devices which solely reference Power Resources which are in the ON state for a given device state can be in that device state. In all other cases, the device is in the D3 (off) state.

!Devices that are enabled to wake the system and that can do so from their current device state can initiate a hardware event which transitions the system state to S0. This transition causes the processor to begin execution at its boot location. The BIOS performs initialization of core functions as required to exit an S3 state and passes control to the firmware resume vector. Please see the ACPI Specification

User’s Manual