Predefined_ACPI_Names.md

Predefined ACPI Names for Objects, Methods, and Resources

The table below lists all reserved ACPI names available in ASL. So if you find a word in your DSDT starting with an underscore (_) and you want to know what it's for, you can look it up in here.

Name	Description
_ACx	Active Cooling – returns the active cooling policy threshold values.
_ADR	Address: (1) returns the address of a device on its parent bus. (2) returns a unique ID for the display output device. (3) resource descriptor field.
_AEI	Designates those GPIO interrupts that shall be handled by OSPM as ACPI events.
_ALC	Ambient Light Chromaticity – returns the ambient light color chromaticity.
_ALI	Ambient Light Illuminance – returns the ambient light brightness.
_ALN	Alignment – base alignment, resource descriptor field.
_ALP	Ambient Light Polling – returns the ambient light sensor polling frequency.
_ALR	Ambient Light Response – returns the ambient light brightness to display brightness mappings.
_ALT	Ambient Light Temperature – returns the ambient light color temperature.
_ALx	Active List – returns a list of active cooling device objects.
_ART	Active cooling Relationship Table – returns thermal relationship information between platform devices and fan devices.
_ASI	Address Space Id – resource descriptor field.
_ASZ	Access Size – resource descriptor field.
_ATT	Type-Specific Attribute – resource descriptor field.
_BAS	Base Address – range base address, resource descriptor field.
_BBN	Bios Bus Number – returns the PCI bus number returned by the platform firmware.
_BCL	Brightness Control Levels – returns a list of supported brightness control levels.
_BCM	Brightness Control Method – sets the brightness level of the display device.
_BCT	Battery Charge Time – returns time remaining to complete charging battery.
_BDN	Bios Dock Name – returns the Dock ID returned by the platform firmware.
_BIF	Battery Information – returns a Control Method Battery information block.
_BIX	Battery Information Extended – returns a Control Method Battery extended information block.
_BLT	Battery Level Threshold – set battery level threshold preferences.
_BM	Bus Master – resource descriptor field.
_BMA	Battery Measurement Averaging Interval – Sets battery measurement averaging interval.
_BMC	Battery Maintenance Control – Sets battery maintenance and control features.
_BMD	Battery Maintenance Data – returns battery maintenance, control, and state data.
_BMS	Battery Measurement Sampling Time – Sets the battery measurement sampling time.
_BPC	Battery Power Characteristics
_BPS	Battery Power State
_BPT	Battery Power Threshold
_BQC	Brightness Query Current – returns the current display brightness level.
_BST	Battery Status – returns a Control Method Battery status block.
_BTH	Battery Throttle Limit - specifies the thermal throttle limit of battery for the firmware when engaging charging.
_BTM	Battery Time – returns the battery runtime.
_BTP	Battery Trip Point – sets a Control Method Battery trip point.
_CBA	Configuration Base Address – returns the base address of the MMIO range corresponding to the Enhanced Configuration Access Mechanism for a PCI Express or Compute Express Link host bus. The full description for the _CBA object resides in the PCI Firmware Specification. A reference to that specification is found in the “Links to ACPI-Related Documents” (http://uefi.org/acpi) under the heading “PCI SIG”.
_CBR	CXL Host Bridge Register Info
_CCA	Cache Coherency Attribute – specifies whether a device and its descendants support hardware managed cache coherency.
_CDM	Clock Domain – returns a logical processor’s clock domain identifier.
_CID	Compatible ID – returns a device’s Plug and Play Compatible ID list.
_CLS	Class Code – supplies OSPM with the PCI-defined class, subclass and programming interface for a device. Optional.
_CPC	Continuous Performance Control – declares an interface that allows OSPM to transition the processor into a performance state based on a continuous range of allowable values.
_CRS	Current Resource Settings – returns the current resource settings for a device.
_CRT	Critical Temperature – returns the shutdown critical temperature.
_CSD	C State Dependencies – returns a list of C-state dependencies.
_CST	C States – returns a list of supported C-states.
_CWS	Clear Wake Status – Clears the wake status of a Time and Alarm Control Method Device.
_DBT	Debounce Timeout -Debounce timeout setting for a GPIO input connection, resource descriptor field
_DCK	Dock – sets docking isolation. Presence indicates device is a docking station.
_DCS	Display Current Status – returns status of the display output device.
_DDC	Display Data Current – returns the EDID for the display output device.
_DDN	Dos Device Name – returns a device logical name.
_DEC	Decode – device decoding type, resource descriptor field.
_DEP	Operation Region Dependencies – evaluates to a package and designates device objects that OSPM should assign a higher priority in start ordering due to future operation region accesses.
_DGS	Display Graphics State – returns the current state of the output device.
_DIS	Disable – disables a device.
_DLM	Device Lock Mutex- Designates a mutex as a Device Lock.
_DMA	Direct Memory Access – returns a device’s current resources for DMA transactions.
_DOD	Display Output Devices – enumerate all devices attached to the display adapter.
_DOS	Disable Output Switching – sets the display output switching mode.
_DPL	Device Selection Polarity - The polarity of the Device Selection signal on a SPISerialBus connection, resource descriptor field
_DRS	Drive Strength – Drive strength setting for a GPIO output connection, resource descriptor field
_DSD	Device Specific Data– returns device-specific information.
_DSM	Device Specific Method – executes device-specific functions.
_DSS	Device Set State – sets the display device state.
_DSW	Device Sleep Wake – sets the sleep and wake transition states for a device.
_DTI	Device Temperature Indication – conveys native device temperature to the platform.
_Exx	Edge GPE – method executed as a result of a general-purpose event.
_EC	Embedded Controller – returns EC offset and query information.
_EDL	Eject Device List – returns a list of devices that are dependent on a device (docking).
_EJD	Ejection Dependent Device – returns the name of dependent (parent) device (docking).
_EJx	Eject – begin or cancel a device ejection request (docking).
_END	Endian-ness – Endian orientation of a UART SerialBus connection, resource descriptor field
_EVT	Event Method - Event method for GPIO-signaled events numbered larger than 255.
_FDE	Floppy Disk Enumerate – returns floppy disk configuration information.
_FDI	Floppy Drive Information – returns a floppy drive information block.
_FDM	Floppy Drive Mode – sets a floppy drive speed.
_FIF	Fan Information – returns fan device information.
_FIT	Firmware Interface Table - returns a list of NFIT Structures.
_FIX	Fixed Register Resource Provider – returns a list of devices that implement FADT register blocks.
_FLC	Flow Control – Flow Control mechanism for a UART SerialBus connection, resource descriptor field
_FPS	Fan Performance States – returns a list of supported fan performance states.
_FSL	Fan Set Level – Control method that sets the fan device’s speed level (performance state).
_FST	Fan Status – returns current status information for a fan device.
_GAI	Get Averaging Interval – returns the power meter averaging interval.
_GCP	Get Capabilities – Returns the capabilities of a Time and Alarm Control Method Device
_GHL	Get Hardware Limit – returns the hardware limit enforced by the power meter.
_GL	Global Lock – OS-defined Global Lock mutex object.
_GLK	Global Lock – returns a device’s Global Lock requirement for device access.
_GPD	Get Post Data – returns the value of the VGA device that will be posted at boot.
_GPE	General Purpose Events: (1) predefined Scope (_GPE). (2) Returns the SCI interrupt associated with the Embedded Controller.
_GRA	Granularity – address space granularity, resource descriptor field.
_GRT	Get Real Time – Returns the current time from a Time and Alarm Control Method Device.
_GSB	Global System Interrupt Base – returns the GSB for a I/O APIC device.
_GTF	Get Task File – returns a list of ATA commands to restore a drive to default state.
_GTM	Get Timing Mode – returns a list of IDE controller timing information.
_GWS	Get Wake Status – Gets the wake status of a Time and Alarm Control Method Device.
_HE	High-Edge – interrupt triggering, resource descriptor field.
_HID	Hardware ID – returns a device’s Plug and Play Hardware ID.
_HMA	Heterogeneous Memory Attributes - returns a list of HMAT structures.
_HOT	Hot Temperature – returns the critical temperature for sleep (entry to S4).
_HPP	Hot Plug Parameters – returns a list of hot-plug information for a PCI device.
_HPX	Hot Plug Parameter Extensions – returns a list of hot-plug information for a PCI device. Supersedes _HPP.
_HRV	Hardware Revision– supplies OSPM with the device’s hardware revision. Optional.
_IFT	IPMI Interface Type. See the Intelligent Platform Management Interface Specification at “Links to ACPI-Related Documents” (http://uefi.org/acpi) under the heading “Server Platform Management Interface Table”.
_INI	Initialize – performs device specific initialization.
_INT	Interrupts – interrupt mask bits, resource descriptor field.
_IOR	IO Restriction – IO restriction setting for a GPIO IO connection, resource descriptor field
_IRC	Inrush Current – presence indicates that a device has a significant inrush current draw.
_Lxx	Level GPE – Control method executed as a result of a general-purpose event.
_LCK	Lock – locks or unlocks a device (docking).
_LEN	Length – range length, resource descriptor field.
_LID	Lid – returns the open/closed status of the lid on a mobile system.
_LIN	Lines in Use - Handshake lines in use in a UART SerialBus connection, resource descriptor field
_LL	Low Level – interrupt polarity, resource descriptor field.
_LPI	Low Power Idle States – returns the list of low power idle states supported by a processor or processor container.
_LSI	Label Storage Information – Returns information about the Label Storage Area associated with the NVDIMM object, including its size.
_LSR	Label Storage Read – Returns label data from the Label Storage Area of the NVDIMM object.
_LSW	Label Storage Write – Writes label data in to the Label Storage Area of the NVDIMM object.
_MAF	Maximum Address Fixed – resource descriptor field.
_MAT	Multiple Apic Table Entry – returns a list of Interrupt Controller Structures.
_MAX	Maximum Base Address – resource descriptor field.
_MBM	Memory Bandwidth Monitoring Data – returns bandwidth monitoring data for a memory device.
_MEM	Memory Attributes – resource descriptor field.
_MIF	Minimum Address Fixed – resource descriptor field.
_MIN	Minimum Base Address – resource descriptor field.
_MLS	Multiple Language String – returns a device description in multiple languages.
_MOD	Mode –Resource descriptor field
_MSG	Message – sets the system message waiting status indicator.
_MSM	Memory Set Monitoring – sets bandwidth monitoring parameters for a memory device.
_MTL	Minimum Throttle Limit – returns the minimum throttle limit of a specific thermal.
_MTP	Memory Type – resource descriptor field.
_NTT	Notification Temperature Threshold – returns a threshold for device temperature change that requires platform notification.
_OFF	Off – sets a power resource to the off state.
_ON	On – sets a power resource to the on state.
_OS	Operating System – returns a string that identifies the operating system.
_OSC	Operating System Capabilities – inform AML of host features and capabilities.
_OSI	Operating System Interfaces – returns supported interfaces, behaviors, and features.
_OST	Ospm Status Indication – inform AML of event processing status.
_PAI	Power Averaging Interval – sets the averaging interval for a power meter.
_PAR	Parity – Parity for a UART SerialBus connection, resource descriptor field
_PCL	Power Consumer List – returns a list of devices powered by a power source.
_PCT	Performance Control – returns processor performance control and status registers.
_PDC	Processor Driver Capabilities – inform AML of processor driver capabilities.
_PDL	P-state Depth Limit – returns the lowest available performance P-state.
_PHA	Clock Phase – Clock phase for a SPISerialBus connection, resource descriptor field
_PIC	PIC – inform AML of the interrupt model in use.
_PIF	Power Source Information – returns a Power Source information block.
_PIN	Pin List – List of GPIO pins described, resource descriptor field.
_PLD	Physical Location of Device – returns a device’s physical location information.
_PMC	Power Meter Capabilities – returns a list of Power Meter capabilities info.
_PMD	Power Metered Devices – returns a list of devices that are measured by the power meter device.
_PMM	Power Meter Measurement – returns the current value of the Power Meter.
_POL	Polarity – Resource descriptor field
_PPC	Performance Present Capabilites – returns a list of the performance states currently supported by the platform.
_PPE	Polling for Platform Error – returns the polling interval to retrieve Corrected Platform Error information.
_PPI	Pin Configuration – Pin configuration for a GPIO connection, resource descriptor field
_PR	Processor – predefined scope for processor objects.
_PR0	Power Resources for D0 – returns a list of dependent power resources to enter state D0 (fully on).
_PR1	Power Resources for D1 – returns a list of dependent power resources to enter state D1.
_PR2	Power Resources for D2 – returns a list of dependent power resources to enter state D2.
_PR3	Power Resources for D3hot – returns a list of dependent power resources to enter state D3hot.
_PRE	Power Resources for Enumeration - Returns a list of dependent power resources to enumerate devices on a bus.
_PRL	Power Source Redundancy List – returns a list of power source devices in the same redundancy grouping.
_PRR	Power Resource for Reset – executes a reset on the associated device or devices.
_PRS	Possible Resource Settings – returns a list of a device’s possible resource settings.
_PRT	Pci Routing Table – returns a list of PCI interrupt mappings.
_PRW	Power Resources for Wake – returns a list of dependent power resources for waking.
_PS0	Power State 0 – sets a device’s power state to D0 (device fully on).
_PS1	Power State 1 – sets a device’s power state to D1.
_PS2	Power State 2 – sets a device’s power state to D2.
_PS3	Power State 3 – sets a device’s power state to D3 (device off).
_PSC	Power State Current – returns a device’s current power state.
_PSD	Power State Dependencies – returns processor P-State dependencies.
_PSE	Power State for Enumeration
_PSL	Passive List – returns a list of passive cooling device objects.
_PSR	Power Source – returns the power source device currently in use.
_PSS	Performance Supported States – returns a list of supported processor performance states.
_PSV	Passive – returns the passive trip point temperature.
_PSW	Power State Wake – sets a device’s wake function.
_PTC	Processor Throttling Control – returns throttling control and status registers.
_PTP	Power Trip Points – sets trip points for the Power Meter device.
_PTS	Prepare To Sleep – inform the platform of an impending sleep transition.
_PUR	Processor Utilization Request – returns the number of processors that the platform would like to idle.
_PXM	Proximity – returns a device’s proximity domain identifier.
_Qxx	Query – Embedded Controller query and SMBus Alarm control method.
_RBO	Register Bit Offset – resource descriptor field.
_RBW	Register Bit Width – resource descriptor field.
_RDI	Resource Dependencies for Idle - returns the list of power resource dependencies for system level low power idle states.
_REG	Region – inform AML code of an operation region availability change.
_REV	Revision – returns the revision of the ACPI specification that is implemented.
_RMV	Remove – returns a device’s removal ability status (docking).
_RNG	Range – memory range type, resource descriptor field.
_ROM	Read-Only Memory – returns a copy of the ROM data for a display device.
_RST	Device Reset – executes a reset on the associated device or devices.
_RT	Resource Type – resource descriptor field.
_RTV	Relative Temperature Values – returns temperature value information.
_RW	Read-Write Status – resource descriptor field.
_RXL	Receive Buffer Size - Size of the receive buffer in a UART Serialbus connection, resource descriptor field.
_S0	S0 System State – returns values to enter the system into the S0 state.
_S1	S1 System State – returns values to enter the system into the S1 state.
_S2	S2 System State – returns values to enter the system into the S2 state.
_S3	S3 System State – returns values to enter the system into the S3 state.
_S4	S4 System State – returns values to enter the system into the S4 state.
_S5	S5 System State – returns values to enter the system into the S5 state.
_S1D	S1 Device State – returns the highest D-state supported by a device when in the S1 state.
_S2D	S2 Device State – returns the highest D-state supported by a device when in the S2 state.
_S3D	S3 Device State – returns the highest D-state supported by a device when in the S3 state.
_S4D	S4 Device State – returns the highest D-state supported by a device when in the S4 state.
_S0W	S0 Device Wake State – returns the lowest D-state that the device can wake itself from S0.
_S1W	S1 Device Wake State – returns the lowest D-state for this device that can wake the system from S1.
_S2W	S2 Device Wake State – returns the lowest D-state for this device that can wake the system from S2.
_S3W	S3 Device Wake State – returns the lowest D-state for this device that can wake the system from S3.
_S4W	S4 Device Wake State – returns the lowest D-state for this device that can wake the system from S4.
_SB	System Bus – scope for device and bus objects.
_SBS	Smart Battery Subsystem – returns the subsystem configuration.
_SCP	Set Cooling Policy – sets the cooling policy (active or passive).
_SDD	Set Device Data – sets data for a SATA device.
_SEG	Segment – returns a device’s PCI Segment Group number.
_SHL	Set Hardware Limit – sets the hardware limit enforced by the Power Meter.
_SHR	Shareable - interrupt share status, resource descriptor field.
_SI	System Indicators – predefined scope.
_SIZ	Size – DMA transfer size, resource descriptor field.
_SLI	System Locality Information – returns a list of NUMA system localities.
_SLV	Slave Mode – Slave mode setting for a SerialBus connection, resource descriptor field.
_SPD	Set Post Device – sets which video device will be posted at boot.
_SPE	Connection Speed – Connection speed for a SerialBus connection, resource descriptor field
_SRS	Set Resource Settings – sets a device’s resource allocation.
_SRT	Set Real Time – Sets the current time to a Time and Alarm Control Method Device.
_SRV	IPMI Spec Revision. See the Intelligent Platform Management Interface Specification at “Links to ACPI-Related Documents” (http://uefi.org/acpi) under the heading “Server Platform Management Interface Table”.
_SST	System Status – sets the system status indicator.
_STA	Status : (1) returns the current status of a device. (2) Returns the current on or off state of a Power Resource.
_STB	Stop Bits - Number of stop bits used in a UART SerialBus connection, resource descriptor field
_STM	Set Timing Mode – sets an IDE controller transfer timings.
_STP	Set Expired Timer Wake Policy – sets expired timer policies of the wake alarm device.
_STR	String – returns a device’s description string.
_STV	Set Timer Value – set timer values of the wake alarm device.
_SUB	Supplies OSPM with the device’s Subsystem ID. Optional.
_SUN	Slot User Number – returns the slot unique ID number.
_SWS	System Wake Source – returns the source event that caused the system to wake.
_T_x	Temporary – reserved for use by ASL compilers.
_TC1	Thermal Constant 1 – returns TC1 for the passive cooling formula.
_TC2	Thermal Constant 2 – returns TC2 for the passive cooling formula.
_TDL	T-State Depth Limit – returns the _TSS entry number of the lowest power throttling state.
_TFP	Thermal Fast Sampling Period - returns the thermal sampling period for passive cooling.
_TIP	Expired Timer Wake Policy – returns timer policies of the wake alarm device.
_TIV	Timer Values – returns remaining time of the wake alarm device.
_TMP	Temperature – returns a thermal zone’s current temperature.
_TPC	Throttling Present Capabilities – returns the current number of supported throttling states.
_TPT	Trip Point Temperature – inform AML that a devices’ embedded temperature sensor has crossed a temperature trip point.
_TRA	Translation – address translation offset, resource descriptor field.
_TRS	Translation Sparse – sparse/dense flag, resource descriptor field.
_TRT	Thermal Relationship Table – returns thermal relationships between platform devices.
_TSD	Throttling State Dependencies – returns a list of T-state dependencies.
_TSF	Type-Specific Flags – resource descriptor field.
_TSN	Thermal Sensor Device - returns a reference to the thermal sensor reporting a zone temperature
_TSP	Thermal Sampling Period – returns the thermal sampling period for passive cooling.
_TSS	Throttling Supported States – returns supported throttling state information.
_TST	Temperature Sensor Threshold – returns the minimum separation for a device’s temperature trip points.
_TTP	Translation Type – translation/static flag, resource descriptor field.
_TTS	Transition To State – inform AML of an S-state transition.
_TXL	Transmit Buffer Size – Size of the transmit buffer in a UART Serialbus connection, resource descriptor field
_TYP	Type – DMA channel type (speed), resource descriptor field.
_TZ	Thermal Zone – predefined scope: ACPI 1.0.
_TZD	Thermal Zone Devices – returns a list of device names associated with a Thermal Zone.
_TZM	Thermal Zone Member – returns a reference to the thermal zone of which a device is a member.
_TZP	Thermal Zone Polling – returns a Thermal zone’s polling frequency.
_UID	Unique ID – return a device’s unique persistent ID.
_UPC	USB Port Capabilities – returns a list of USB port capabilities.
_UPD	User Presence Detect – returns user detection information.
_UPP	User Presence Polling – returns the recommended user presence polling interval.
_VEN	Vendor-defined Data – Vendor-defined data for a GPIO or SerialBus connection, resource descriptor field
_VPO	Video Post Options – returns the implemented video post options.
_WAK	Wake – inform AML that the system has just awakened.
_WPC	Wireless Power Calibration - returns the notifier to wireless power controller.
_WPP	Wireless Power Polling - returns the recommended polling frequency
_Wxx	Wake Event – method executed as a result of a wake event.

SOURCE: ACPI Specs, Chpt. 5.6.8: "Predefined ACPI Names for Objects, Method and Resources"