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1.11.1.1
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 board 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
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/S5
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)
G3 – mechanical
off
AC power is
disconnected
from the
computer.
No power to the
system.
No power
D3 – no power for
wake-up logic,
except when
provided by battery
or external source.
No power to the
system. Service can be
performed safely.
Notes:
1.
Total system power is dependent on the system configuration, including add-in boards and peripherals powered
by the system chassis’ power supply.
2.
Dependent on the standby power consumption of wake-up devices used in the system.
