Advanced Configuration and Power Interface Specification

ACPI-Defined Devices and Device-Specific Objects
Table 9-268 Usage Types and Interrupt Polarity
Usage Type
OSC - One Shot
Control
MC - Momentary
Control
RTC - Re-trigger
Control
OOC - On/Off
Control
Interrupt
Polarity
ActiveHigh/
ActiveLow
ActiveBoth
ActiveBoth
ActiveHigh/
ActiveLow
OR
ActiveBoth
Explanation
An interrupt should be triggered on a button press. This is for a
toggle button. On every such event (interrupt), the Operating
System will toggle the internal property of the entity that it controls.
Example: Mute button
An interrupt should be triggered on both the button press and
release. Example: Left mouse button.
An interrupt should be triggered on both the button press and
release. While the button is pressed, the Operating System will
repeatedly re-execute the action that it would take when the button
is pressed. Example: A Volume Up button when pressed and held,
will repeatedly increment the Volume.
ActiveHigh/ActiveLow polarity should be specified if implemented
as a button that goes back to its initial state automatically. E.g. A
Push Button or a spring-loaded Slider switch. Only one interrupt
should be fired for press/release pair.
Example: A spring-loaded Wireless Radio Slider Switch.
ActiveBoth polarity should be specified if implemented as a button
that stays in its state until the user moves it again. E.g. A button that
stays in pressed state, or a Slider switch that sticks to its position.
Example: Wireless Radio Slider Switch.
9.19.2 Button Usages and Collections
The HID Usage tables have an extensive list of Standardized Usages for various kinds of buttons.
Some of the common buttons found on Computing devices and their Usages are listed in Table 9-
269.
For the full list, see “HID Usage Tables”, available from “Links to ACPI-Related Documents”
(http://uefi.org/acpi) under the heading "HID Usage Tables".
Buttons are grouped under a HID Collection. Several HID Collections are commonly understood by
Operating Systems, e.g., Keyboard Collection, Consumer Controls Collection, Wireless Radio
Controls Collection, etc.
Table 9-269 Common HID Button Usages
Button Usage Page / Usage Usage
Type
Power
Volume Up
Generic Desktop Page
(0x01)
System Power Down
(0x01)
Consumer Page (0x0C)
Volume Increment (0xE9)
Interrupt
Polarity
Spec Reference
OSC ActiveBoth 1 HID Usage Tables 1.12
Section 4
RTC ActiveBoth HID Usage Tables 1.12
Section 15
Version 6.0 553