Advanced Configuration and Power Interface Specification

Advanced Configuration and Power Interface Specification
6.5.8.1 Example
Device(\_SB.TC3) {
…
OperationRegion(OPRG,
GenericSerialBus,
0x00,
0x100)
…
}
Device(\_SB.TP1) {
…
Name (_DEP, Package() {\_SB.TC3})
…
}
6.5.9 _FIT (Firmware Interface Table)
This method evaluates to a buffer returning data in the format of a series of NFIT Type Structure
Entries. This method may appear under device with _HID of ACPI0012. _FIT method, when
present, is always evaluated by OSPM.
_FIT under ACPI0012 device returns all the entries in the NFIT.
NFIT Update Notification (Notify Code 0x80) is sent to ACPI device with _HID of ACPI0012 to
notify OSPM that it needs to re-evaluate the _FIT method.
Note: NFIT is an ACPI table enumerated at OS boot. In case of hot plug of NVDIMMs, the
corresponding NFIT structures will not be present in NFIT. _FIT method is also used to provide
these structures dynamically during hot plug.
Arguments:
None
Return Value:
A Buffer containing a list of NFIT Type structure entries
Example ASL for _FIT usage:
Scope (\_SB) {
Device (XYZ) {
Name(_HID, “ACPI0012”)
Method (_FIT, 0) {
Return (FITD)
}
Method (_DSM, …) {
…
}
}
OperationRegion (TABD, SystemMemory, // Physical address of first
// data byte of NFIT ACPI table, Length of table)
Field (TABD, ByteAcc, NoLock, Preserve) {
FITD, Length of tables
}
} // end scope SB
388 April, 2015 Version 6.0