Advanced Configuration and Power Interface Specification

Advanced Configuration and Power Interface Specification
entries corresponding to either the ACPI processor ID of the Processor object or the value returned
by the _UID object under a Processor device.
When _MAT appears under an I/O APIC, OSPM processes I/O APIC (Section 5.2.12.3, “I/O APIC
Structure”), I/O SAPIC (Section 5.2.12.9, “I/O SAPIC Structure”), non-maskable interrupt sources
(Section 5.2.12.6, “Non-Maskable Interrupt Source Structure”), interrupt source overrides
(Section 5.2.12.5 “Interrupt Source Override Structure”), and platform interrupt source structure
(Section 5.2.12.11, “Platform Interrupt Source Structure”) entries returned from the object’s
evaluation. Other entry types are ignored by OSPM.
Arguments:
None
Return Value:
A Buffer containing a list of APIC structure entries
Example ASL for _MAT usage:
Scope(\_SB) {
Device(PCI0) {
Name(_HID, EISAID("PNP0A03"))
Method (_CRS,0){
}
Name(_PRT, Package(){
})
// Root PCI Bus
// Need _HID for root device
// Need current resources for root device
// Return current resources for root bridge 0
// Need PCI IRQ routing for PCI bridge
// Package with PCI IRQ routing table information
Device (P64A) {
// P64A ACPI
Name(_ADR,0)
OperationRegion(TABD, SystemMemory, // Physical address of first
// data byte of multiple ACPI table, Length of tables)
Field (TABD, ByteAcc, NoLock, Preserve){
MATD, Length of tables x 8
}
Method(_MAT, 0){
Return (MATD)
}
} // end P64A
} // end PCI0
} // end scope SB
6.2.11 _OSC (Operating System Capabilities)
This optional object is a control method that is used by OSPM to communicate to the platform the
feature support or capabilities provided by a device’s driver. This object is a child object of a device
and may also exist in the \_SB scope, where it can be used to convey platform wide OSPM
capabilities. When supported, _OSC is invoked by OSPM immediately after placing the device in
the D0 power state. Device specific objects are evaluated after _OSC invocation. This allows the
values returned from other objects to be predicated on the OSPM feature support / capability
information conveyed by _OSC. OSPM may evaluate _OSC multiple times to indicate changes in
OSPM capability to the device but this may be precluded by specific device requirements. As such,
_OSC usage descriptions in Section 9, “ACPI-Defined Devices and Device Specific Objects”, or
312 April, 2015 Version 6.0