ADC Home > Reference Library > Reference > Hardware & Drivers > I/O Kit Framework Reference

 

IOPM.h

Includes:

Overview

Defines power management constants and keys used by both in-kernel and user space power management.

Discussion

IOPM.h defines a range of power management constants used in several in-kernel and user space APIs. Most significantly, the IOPMPowerFlags used to specify the fields of an IOPMPowerState struct are defined here.

Most of the constants defined in IOPM.h are deprecated or for Apple internal use only, and are not elaborated on in headerdoc.


Typedefs

IOPMPowerFlags

Bits are used in defining capabilityFlags, inputPowerRequirements, and outputPowerCharacter in the IOPMPowerState structure.

See Also:

IOPMPowerFlags

 
typedef unsigned long IOPMPowerFlags;
Discussion

These bits may be bitwise-OR'd together in the IOPMPowerState capabilityFlags field, the outputPowerCharacter field, and/or the inputPowerRequirement field.

The comments clearly mark whether each flag should be used in the capabilityFlags field, outputPowerCharacter field, and inputPowerRequirement field, or all three.

The value of capabilityFlags, inputPowerRequirement or outputPowerCharacter may be 0. Most drivers implement their 'OFF' state, used when asleep, by defininf each of the 3 fields as 0.

The bits listed below are only the most common bits used to define a device's power states. Your device's IO family may require that your device specify other input or output power flags to interact properly. Consult family-specific documentation to determine if your IOPower plane parents or children require other power flags; they probably don't.

Enumerations

IOPMPowerFlags

Bits are used in defining capabilityFlags, inputPowerRequirements, and outputPowerCharacter in the IOPMPowerState structure.

See Also:

IOPMPowerFlags

 
enum { 
    kIOPMPowerOn = 0x00000002, 
    kIOPMDeviceUsable = 0x00008000, 
    kIOPMLowPower = 0x00010000, 
    kIOPMPreventIdleSleep = 0x00000040, 
    kIOPMSleepCapability = 0x00000004, 
    kIOPMRestartCapability = 0x00000080, 
    kIOPMSleep = 0x00000001, 
    kIOPMRestart = 0x00000080 
};
Constants
kIOPMPowerOn

Indicates the device is on, requires power, and provides power. Useful as a: Capability, InputPowerRequirement, OutputPowerCharacter

kIOPMDeviceUsable

Indicates the device is usable in this state. Useful only as a Capability

kIOPMLowPower

Indicates device is in a low power state. May be bitwis-OR'd together with kIOPMDeviceUsable flag, to indicate the device is still usable.

A device with a capability of kIOPMLowPower may: Require either 0 or kIOPMPowerOn from its power parent Offer either kIOPMLowPower, kIOPMPowerOn, or 0 (no power at all) to its power plane children.

Useful only as a Capability, although USB drivers should consult USB family documentation for other valid circumstances to use the kIOPMLowPower bit.

kIOPMPreventIdleSleep

In the capability field of a power state, disallows idle system sleep while the device is in that state.

For example, displays and disks set this capability for their ON power state; since the system may not idle sleep while the display (and thus keyboard or mouse) or the disk is active.

Useful only as a Capability.

kIOPMSleepCapability

Used only by certain IOKit Families (USB). Not defined or used by generic Power Management. Read your family documentation to see if you should define a powerstate using these capabilities.

kIOPMRestartCapability

Used only by certain IOKit Families (USB). Not defined or used by generic Power Management. Read your family documentation to see if you should define a powerstate using these capabilities.

kIOPMSleep

Used only by certain IOKit Families (USB). Not defined or used by generic Power Management. Read your family documentation to see if you should define a powerstate using these capabilities.

kIOPMRestart

Used only by certain IOKit Families (USB). Not defined or used by generic Power Management. Read your family documentation to see if you should define a powerstate using these capabilities.

Discussion

These bits may be bitwise-OR'd together in the IOPMPowerState capabilityFlags field, the outputPowerCharacter field, and/or the inputPowerRequirement field.

The comments clearly mark whether each flag should be used in the capabilityFlags field, outputPowerCharacter field, and inputPowerRequirement field, or all three.

The value of capabilityFlags, inputPowerRequirement or outputPowerCharacter may be 0. Most drivers implement their 'OFF' state, used when asleep, by defininf each of the 3 fields as 0.

The bits listed below are only the most common bits used to define a device's power states. Your device's IO family may require that your device specify other input or output power flags to interact properly. Consult family-specific documentation to determine if your IOPower plane parents or children require other power flags; they probably don't.


Did this document help you?
Yes: Tell us what works for you.
It’s good, but: Report typos, inaccuracies, and so forth.
It wasn’t helpful: Tell us what would have helped.

 

Last Updated: 2009-02-23