Intel® NUC 12 Extreme / Pro X
ACPI
ACPI gives the operating system direct control over the power management and Plug and Play functions of a computer. The use of ACPI with this board requires an operating system that provides full ACPI support. ACPI features include:
- Plug and Play (including bus and device enumeration)
- Power management control of individual devices, add-in boards (some add-in boards may require an ACPI-aware driver), video displays, and hard disk drives
- Methods for achieving less than 15-watt system operation in the power-on/standby sleeping state
- A Soft-off feature that enables the operating system to power-off the computer
- Support for a front panel power and sleep mode switch
Table 3 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 3. 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 G2/G5 – Soft off) | Less than four seconds | Power-on(ACPI G0 – working state) |
On(ACPI G0 – working state) | Less than four seconds | Soft-off/Standby(ACPI G1 – sleeping state) Note |
On(ACPI G0 – working state) | More than six seconds | Fail safe power-off(ACPI G2/G5 – Soft off) |
Sleep(ACPI G1 – sleeping state) | Less than four seconds | Wake-up(ACPI G0 – working state) |
Sleep (ACPI G1 – sleeping state) | More than six seconds | Power-off(ACPI G2/G5 – Soft off) |
Note: Depending on power management settings in the 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 into a low-power state.
Table 4 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 4. Power States and Targeted System Power
Global States | Sleeping States | Processor States | Device States |
G0 – working state | S0 – working | C0 – working | D0 – working state. |
G1 – sleeping state | S3 – Suspend to RAM. Context saved to RAM. | No power | D3 – no power except for wake-up logic. |
G1 – sleeping state | S4 – Suspend to disk. Context saved to disk. | No power | D3 – no power except for wake-up logic. |
G2/S5 | S5 – Soft off. Context not saved. Cold boot is required. | No power | D3 – no power except for wake-up logic. |
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. |
Notes:
- Total system power is dependent on the system configuration, including add-in boards and peripherals powered by the system chassis’ power supply.
- Dependent on the standby power consumption of wake-up devices used in the system.
Wake-up Devices and Events
Table 5 lists the devices or specific events that can wake the computer from specific states.
Table 5. Wake-up Devices and Events
Devices/events that wake up the system… | …from this sleep state | Comments |
Power switch | S3, S4, S51 | |
RTC alarm | S3, S4, S51 | Monitor to remain in sleep state |
LAN | S3, S4, S51, 3 | “S5 WOL after G3” must be supported; monitor to remain in sleep state |
WIFI | S3, S4, S51, 3 | Monitor to remain in sleep state |
Bluetooth | S31, S4 | |
USB | S3, S4, S51, 2, 3 | Wake S4, S5 controlled by BIOS option (not after G3) |
PCIE | S3, S4 | Via WAKE; monitor to remain in sleep state |
HDMI CEC | S3, S4, S51 | Emulates power button push |
Notes:
1. S4 implies operating system support only.
2. Will not wake from Deep S4/S5. USB S4/S5 Power is controlled by BIOS. USB S5 wake is controlled by BIOS. USB S4 wake is controlled by OS driver, not just BIOS option.
3. Windows Fast startup will block wake from LAN and USB from S5.
NOTE
The use of these wake events from an ACPI state requires an operating system that provides full ACPI support. In addition, software, drivers, and peripherals must fully support ACPI wake events.