Advanced Configuration and Power Interface Specification

ACPI-Defined Devices and Device-Specific Objects
A GPE Block device must have a _HID or a _CID of “ACPI0006.”
Note: A system designer must describe the GPE block necessary to bootstrap the system in the FADT
as a GPE0/GPE1 block. GPE Block devices cannot be used to implement these GPE inputs.
A GPE Block Device must contain the _Lxx, _Exx, _Wxx, _CRS, _PRS, and _SRS methods
required to use and program that block.
To represent the GPE block associated with the FADT, the system designer shouldinclude in the
namespace a Device object with the ACPI0006 _HID that contains no _CRS, _PRS, _SRS, _Lxx,
_Exx, or _Wxx methods. OSPM assumes that the first such ACPI0006 device is the GPE Block
Device that is associated with the FADT GPEs. (See the example below).
// ASL example of a standard GPE block device
Device(\_SB.PCI0.GPE1) {
Name(_HID, ”ACPI0006”)
Name(_UID, 2)
Name(_CRS, Buffer () {
IO(Decode16, FC00, FC03, 4, 4,)
IRQ( Level, ActiveHigh, Shared,) { 5 }
})
}
Method(_L02) { … }
Method(_E07) { … }
Method(_W04) { … }
// ASL example of a GPE block device that refers to the FADT GPEs.
// Cannot contain any _Lxx, _Exx, _Wxx, _CRS, _PRS, or. _SRS methods.
Device(\_SB.PCI0.GPE0) {
Name(_HID,”ACPI0006”)
Name(_UID,1)
}
Notice that it is legal to replace the I/O descriptors with Memory descriptors if the register is
memory mapped.
If the system must run any GPEs to bootstrap the system (for example, when Embedded Controller
events are required), the associated block of GPEs must be described in the FADT. This register
block is not relocatable and will always be available for the life of the operating system boot.
A GPE block associated with the ACPI0006 _HID can be stopped, ejected, reprogrammed, and so
on. The system can also have multiple such GPE blocks.
9.10.1 Matching Control Methods for Events in a GPE Block Device
When a GPE Device raises an interrupt, OSPM executes a corresponding control method (as
described in Section 5.6.4.1.1, “Queuing the Matching Control Method for Execution”). These
control methods (of the form _Lxx, _Exx, and _Wxx) for GPE Devices are not within the \_GPE
namespace. They are children of the GPE Block device.
For example:
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