
Functional Architecture
S875WP1-E TPS
Revision 4.0
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Table 5 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 5. Effects of Pressing the Power Switch
If the system is in this state…
…and the power switch is
pressed for
…the system enters this state
Off
(ACPI S5 – Soft off)
Less than four seconds
Power-on
(ACPI S0 – working state)
On
(ACPI S0 – working state)
Less than four seconds
Soft-off/Standby
(ACPI S1 or S3 – sleeping state)
On
(ACPI S0 – working state)
More than four seconds
Fail safe power-off
(ACPI S5 – Soft off)
Sleep
(ACPI S1 or S3 – sleeping state)
Less than four seconds
Wake-up
(ACPI S0 – working state)
Sleep
(ACPI S1 or S3 – sleeping state)
More than four seconds
Power-off
(ACPI S5 – Soft off)
3.6.1.1
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 6 lists the power states supported by the Server Board S875WP1-E along with the
associated system power targets. See the ACPI specification for a complete description of the
various system and power states.
Table 6. Power States and Targeted System Power
Global States
Sleeping States
Processor
States
Device States
Targeted System
Power (Note 1)
G0 – working
state
S0 – working
C0 – working
D0 – working state. Full power > 30 W
G1 – sleeping
state
S1 – Processor
stopped
C1 – stop
grant
D1, D2, D3 –
device specification
specific.
5 W < power < 52.5 W
G1 – sleeping
state
S3 – Suspend to
RAM. Context
saved to RAM.
No power
D3 – no power
except for wake-up
logic.
Power < 5 W (Note 2)
G1 – sleeping
state
S4 – Suspend to
disk. Context saved
to disk.
No power
D3 – no power
except for wake-up
logic.
Power < 5 W (Note 2)
G2/G5
S5 – Soft off.
Context not saved.
Cold boot is
required.
No power
D3 – no power
except for wake-up
logic.
Power < 5 W (Note 2)