User Manual

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2.13 Intel® Virtualization Technology for Directed I/O
Intel® Virtualization Technology for Directed I/O (Intel® VT-d) allows addresses in incoming I/O
device memory transactions to be remapped to different host addresses. This provides Virtual
Machine Monitor (VMM) software with:
• Improved reliability and security through device isolation using hardware assisted remapping.
• Improved I/O performance and availability by direct assignment of devices.
For information about
Refer to
Intel® Virtualization Technology for Directed I/O
https://software.intel.com/en-
us/node/139035?wapkw=vt+directed+io
2.14 Power Management
Power management is implemented at several levels, including:
• Software support through Advanced Configuration and Power Interface (ACPI)
• Hardware support:
⎯ Power Input
⎯ LAN wake capabilities
⎯ Wake from USB
2.14.1 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