Advanced Configuration and Power Interface Specification

Advanced Configuration and Power Interface Specification
}
Return(0xFFFFFFFF)
}
{
...
Store(Store(P2, \_SB.I2C1.P2), BUFF)
If(LEqual(STAT, 0x00))
//Transaction was _NOT_successful
Return(0xFFFFFFFF)
}
}
Name(_DEP, Package() {"\\_SB.I2C1"}) //Identify the OpRegion dependency for this device
9.19 Generic Buttons Device
The Generic Button device is a standard device for reporting button events via hardware interrupts,
and mapping those interrupts to specific usages defined in the Human Interface Device (HID)
specification. In order to express the functionality of a button to the OS, two pieces of information
are required: Usage of the HID Control, and Usage of the HID Collection that the Control belongs
to. A Usage is a combination of a Usage Page and Usage ID. For example, the Volume Up button is
identified as the Volume Up Usage (Usage Page 0x0C, Usage Id 0xE9) in the Consumer Control
Collection (Usage Page 0x0C, Usage Id 0x01).
The Plug and Play ID of the Generic Button device is ACPI0011.
Note: If the Power button is described using this device, it must also support the Power Button Override
feature defined in Section 4.8.2.2.1.3 Power Button Override.
Table 9-267 Generic Buttons Device Child Objects
Object
_CRS
_DSD
Description
Lists the resources consumed by the Generic Button device. Only interrupt resources (GpioInt()
and Interrupt() ) are valid for this device. Each interrupt listed must signal one distinct button
event.
Provides a list of HID Button Descriptors, as defined by UUID FA6BD625-9CE8-470D-A2C7-
B3CA36C4282E. (See http://www.uefi.org/sites/default/files/resources/_DSD-HIDbuttondescriptor-UUID.pdf).
Only HID 2-state button usages are valid for the descriptors
returned for this device.
Note: If there are more HID Button Descriptors returned by _DSD than there are interrupts listed in
_CRS, behavior is OS-specific.
9.19.1 Button Interrupts
Interrupts for the Generic Buttons Device are required to be edge-triggered and not level-triggered
since there is no interface defined for the driver to quiesce the interrupt line once the interrupt is
received. The polarity (ActiveLow/High vs. ActiveBoth) of the interrupt is determined by the Usage
Type of the HID Usage associated with the interrupt, as described in Table 9-268.
552 April, 2015 Version 6.0