Asus P7H55/USB3 - Manual (Page 58)

2-18 Chapter 2: BIOS information
USB Functions [Enabled]
[Enabled] Enables the USB Host Controllers.
[Disabled] Disables the controllers.
The following items appear only when you set USB Support to [Enabled].
Legacy USB Support [Auto]
[Disabled] Disables the function.
[Enabled] Enables the support for USB devices on legacy operating systems (OS).
[Auto] Allows the system to detect the presence of USB devices at startup. If
detected, the USB controller legacy mode is enabled. If no USB device is
detected, the legacy USB support is disabled.
BIOS EHCI Hand-off [Enabled]
[Disabled] Disables the function.
[Enabled] Enables the support for operating systems without an EHCI hand-off
feature.
2.5.5 PCIPnP
The PCIPnP menu items allow you to change the advanced settings for PCI/PnP devices.
Plug And Play O/S [No]
[Yes] When set to [Yes] and if you install a Plug and Play operating system, the
operating system configures the Plug and Play devices not required for
boot.
[No] When set to [No], BIOS configures all the devices in the system.
2.5.6 Intel VT-d Configuration [Disabled]
[Disabled] Disables the Intel Virtualization Technology for Directed I/O.
[Enabled] Enables the Intel Virtualization Technology for Directed I/O.