Product Description
35
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 11 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 11. 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
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.
