ABI testing symbols¶

Documents interfaces that are felt to be stable,as the main development of this interface has been completed.

The interface can be changed to add new features, but thecurrent interface will not break by doing this, unless graveerrors or security problems are found in them.

Userspace programs can start to rely on these interfaces, but they mustbe aware of changes that can occur before these interfaces move tobe marked stable.

Programs that use these interfaces are strongly encouraged to add theirname to the description of these interfaces, so that the kerneldevelopers can easily notify them if any changes occur.

Defined on fileconfigfs-acpi

This group contains the configuration for user defined ACPItables. The attributes of a user define table are:

aml

• a binary attribute that the user can use tofill in the ACPI aml definitions. Once the amldata is written to this file and the file isclosed the table will be loaded and ACPI deviceswill be enumerated. To check if the operation issuccessful the user must check the error codefor close(). If the operation is successful,subsequent writes to this attribute will fail.

The rest of the attributes are read-only and are valid onlyafter the table has been loaded by filling the aml entry:

signature

• ASCII table signature

length

• length of table in bytes, including the header

revision

• ACPI Specification minor version number

oem_id

• ASCII OEM identification

oem_table_id

• ASCII OEM table identification

oem_revision

• OEM revision number

asl_compiler_id

• ASCII ASL compiler vendor ID

asl_compiler_revision

• ASL compiler version

Defined on fileconfigfs-iio

Industrial IO software devices directory.

Defined on fileconfigfs-iio

Dummy IIO devices directory. Creating a directory here will resultin creating a dummy IIO device in the IIO subsystem.

Defined on fileconfigfs-iio

Industrial IO software triggers directory.

Defined on fileconfigfs-iio

High resolution timers directory. Creating a directory herewill result in creating a hrtimer trigger in the IIO subsystem.

# mount -t configfs none /config/

Defined on fileconfigfs-rdma_cm

RDMA-CM based connections from HCA <hca> at port <port-num>will be initiated with this RoCE type as default.The possible RoCE types are either “IB/RoCE v1” or “RoCE v2”.This parameter has RW access.

Defined on fileconfigfs-rdma_cm

RDMA-CM QPs from HCA <hca> at port <port-num>will be created with this TOS as default.This can be overridden by using the rdma_set_option API.The possible RoCE TOS values are 0-255.

Defined on fileconfigfs-stp-policy

This group is the root of a policy; its name is a concatenationof an stm device name to which this policy applies and anarbitrary string. If <device> part doesn’t match an existingstm device, mkdir will fail with ENODEV; if that device alreadyhas a policy assigned to it, mkdir will fail with EBUSY.

Defined on fileconfigfs-stp-policy

Policy node is a string identifier that software clients willuse to request a master/channel to be allocated and assigned tothem.

Defined on fileconfigfs-stp-policy

Range of channels from which to allocate for users of this node.Write two numbers: the first channel and the last channelnumber.

Defined on fileconfigfs-stp-policy

Range of masters from which to allocate for users of this node.Write two numbers: the first master and the last master number.

Defined on fileconfigfs-stp-policy

STM device to which this policy applies, read only. Same as the<device> component of its parent directory.

Defined on fileconfigfs-stp-policy-p_sys-t

Time interval in milliseconds. Send a CLOCKSYNC packet ifthis many milliseconds have passed since the previousCLOCKSYNC packet from this source. Zero is the default andstands for “never send the CLOCKSYNC”. It makes sense touse this option with sources that generate constant and/orperiodic data, like stm_heartbeat.

Defined on fileconfigfs-stp-policy-p_sys-t

Include payload length in the MIPI SyS-T header, boolean.If enabled, the SyS-T protocol encoder will include payloadlength in each packet’s metadata. This is normally redundantif the underlying transport protocol supports marking messageboundaries (which STP does), so this is off by default.

Defined on fileconfigfs-stp-policy-p_sys-t

Time interval in milliseconds. Include a timestamp in theMIPI SyS-T packet metadata, if this many milliseconds havepassed since the previous packet from this source. Zero isthe default and stands for “never send the timestamp”.

Defined on fileconfigfs-stp-policy-p_sys-t

UUID source identifier string, RW.Default value is randomly generated at the mkdir <node> time.Data coming from trace sources that use this <node> will betagged with this UUID in the MIPI SyS-T packet stream, toallow the decoder to discern between different sourceswithin the same master/channel range, and identify thehigher level decoders that may be needed for each source.

Defined on fileconfigfs-usb-gadget

The attributes of a gadget:

Defined on fileconfigfs-usb-gadget

This group contains a USB gadget’s configurations

Defined on fileconfigfs-usb-gadget

The attributes of a configuration:

Defined on fileconfigfs-usb-gadget

This group contains subdirectories for language-specificstrings for this configuration.

Defined on fileconfigfs-usb-gadget

The attributes:

Defined on fileconfigfs-usb-gadget

This group contains functions available to this USB gadget.

Defined on fileconfigfs-usb-gadget

This group contains “Feature Descriptors” specific for onegadget’s USB interface or one interface group describedby an IAD.

The attributes:

Defined on fileconfigfs-usb-gadget

This group contains “Extended Property Descriptors” specific for onegadget’s USB interface or one interface group describedby an IAD.

The attributes:

Defined on fileconfigfs-usb-gadget-loopback

The attributes:

Defined on fileconfigfs-usb-gadget-sourcesink

The attributes:

Defined on fileconfigfs-usb-gadget-acm

This item contains just one readonly attribute: port_num.It contains the port number of the /dev/ttyGS<n> deviceassociated with acm function’s instance “name”.

Defined on fileconfigfs-usb-gadget-acm

Reported bInterfaceProtocol for the ACM device. For legacyreasons, this defaults to 1 (USB_CDC_ACM_PROTO_AT_V25TER).

Defined on fileconfigfs-usb-gadget-ecm

The attributes:

ifname

• network device interface name associated withthis function instance

qmult

• queue length multiplier for high andsuper speed

host_addr

• MAC address of host’s end of thisEthernet over USB link

dev_addr

• MAC address of device’s end of thisEthernet over USB link

Defined on fileconfigfs-usb-gadget-eem

The attributes:

Defined on fileconfigfs-usb-gadget-ffs

The purpose of this directory is to create and remove it.

A corresponding USB function instance is created/removed.

All attributes are read only:

All other parameters are set through FunctionFS.

Defined on fileconfigfs-usb-gadget-subset

The attributes:

Defined on fileconfigfs-usb-gadget-serial

This item contains just one readonly attribute: port_num.It contains the port number of the /dev/ttyGS<n> deviceassociated with gser function’s instance “name”.

Defined on fileconfigfs-usb-gadget-hid

The attributes:

Defined on fileconfigfs-usb-gadget-mass-storage

The attributes:

Defined on fileconfigfs-usb-gadget-mass-storage

The attributes:

Defined on fileconfigfs-usb-gadget-midi

The attributes:

Defined on fileconfigfs-usb-gadget-midi2

The attributes:

Defined on fileconfigfs-usb-gadget-midi2

This group contains a UMP Endpoint configuration.A new Endpoint starts from 0, and can be up to 3.

The attributes:

Defined on fileconfigfs-usb-gadget-midi2

This group contains a UMP Function Block configuration.A new block starts from 0, and can be up to 31.

The attributes:

Defined on fileconfigfs-usb-gadget-ncm

The attributes:

ifname - network device interface name associated with

this function instance

qmult - queue length multiplier for high and

super speed

host_addr - MAC address of host’s end of this

Ethernet over USB link

dev_addr - MAC address of device’s end of this

Ethernet over USB link

Defined on fileconfigfs-usb-gadget-obex

This item contains just one readonly attribute: port_num.It contains the port number of the /dev/ttyGS<n> deviceassociated with obex function’s instance “name”.

Defined on fileconfigfs-usb-gadget-phonet

This item contains just one readonly attribute: ifname.It contains the network interface name assigned duringnetwork device registration.

Defined on fileconfigfs-usb-gadget-printer

The attributes:

Defined on fileconfigfs-usb-gadget-rndis

The attributes:

Defined on fileconfigfs-usb-gadget-tcm

There are no attributes because all the configurationis performed in the “target” subsystem of configfs.

Defined on fileconfigfs-usb-gadget-uac1

The attributes:

Defined on fileconfigfs-usb-gadget-uac1_legacy

The attributes:

audio_buf_size - audio buffer sizefn_cap - capture pcm device file namefn_cntl - control device file namefn_play - playback pcm device file namereq_buf_size - ISO OUT endpoint request buffer sizereq_count - ISO OUT endpoint request count

Defined on fileconfigfs-usb-gadget-uac2

The attributes:

Defined on fileconfigfs-usb-gadget-uvc

UVC function directory

Defined on fileconfigfs-usb-gadget-uvc

Control descriptors

All attributes read only except enable_interrupt_ep:

Defined on fileconfigfs-usb-gadget-uvc

Class descriptors

Defined on fileconfigfs-usb-gadget-uvc

Full speed control class descriptors

Defined on fileconfigfs-usb-gadget-uvc

Super speed control class descriptors

Defined on fileconfigfs-usb-gadget-uvc

Extension unit descriptors

Defined on fileconfigfs-usb-gadget-uvc

Extension Unit (XU) Descriptor

bLength, bUnitID and iExtension are read-only. All others areread-write.

Defined on fileconfigfs-usb-gadget-uvc

Control header descriptors

Defined on fileconfigfs-usb-gadget-uvc

Specific control header descriptors

dwClockFrequencybcdUVC

Defined on fileconfigfs-usb-gadget-uvc

Processing unit descriptors

Defined on fileconfigfs-usb-gadget-uvc

Default processing unit descriptors

All attributes read only except bmControls, which is read/write:

Defined on fileconfigfs-usb-gadget-uvc

Terminal descriptors

Defined on fileconfigfs-usb-gadget-uvc

Camera terminal descriptors

Defined on fileconfigfs-usb-gadget-uvc

Default camera terminal descriptors

All attributes read only except bmControls, which is read/write:

Defined on fileconfigfs-usb-gadget-uvc

Output terminal descriptors

Defined on fileconfigfs-usb-gadget-uvc

Default output terminal descriptors

All attributes read only except bSourceID:

Defined on fileconfigfs-usb-gadget-uvc

Streaming descriptors

All attributes read only:

Defined on fileconfigfs-usb-gadget-uvc

Streaming class descriptors

Defined on fileconfigfs-usb-gadget-uvc

Full speed streaming class descriptors

Defined on fileconfigfs-usb-gadget-uvc

High speed streaming class descriptors

Defined on fileconfigfs-usb-gadget-uvc

Super speed streaming class descriptors

Defined on fileconfigfs-usb-gadget-uvc

Color matching descriptors

Defined on fileconfigfs-usb-gadget-uvc

Default color matching descriptors

All attributes read/write:

Defined on fileconfigfs-usb-gadget-uvc

Additional color matching descriptors

All attributes read/write:

Defined on fileconfigfs-usb-gadget-uvc

Framebased format descriptors

Defined on fileconfigfs-usb-gadget-uvc

Specific framebased format descriptors

Defined on fileconfigfs-usb-gadget-uvc

Specific framebased frame descriptors

Defined on fileconfigfs-usb-gadget-uvc

Streaming header descriptors

Defined on fileconfigfs-usb-gadget-uvc

Specific streaming header descriptors

All attributes read only:

Defined on fileconfigfs-usb-gadget-uvc

MJPEG format descriptors

Defined on fileconfigfs-usb-gadget-uvc

Specific MJPEG format descriptors

All attributes read only,except bmaControls and bDefaultFrameIndex:

Defined on fileconfigfs-usb-gadget-uvc

Specific MJPEG frame descriptors

Defined on fileconfigfs-usb-gadget-uvc

Uncompressed format descriptors

Defined on fileconfigfs-usb-gadget-uvc

Specific uncompressed format descriptors

Defined on fileconfigfs-usb-gadget-uvc

Specific uncompressed frame descriptors

Defined on fileconfigfs-usb-gadget

This group contains “OS String” extension handling attributes.

Defined on fileconfigfs-usb-gadget

This group contains subdirectories for language-specificstrings for this gadget.

Defined on fileconfigfs-usb-gadget

The attributes:

Defined on fileconfigfs-usb-gadget

This group contains “WebUSB” extension handling attributes.

7,160,424069,-;pci_root PNP0A03:00: host bridge window [io  0x0000-0x0cf7] (ignored) SUBSYSTEM=acpi DEVICE=+acpi:PNP0A03:006,339,5140900,-;NET: Registered protocol family 1030,340,5690716,-;udevd[80]: starting version 181

Defined on fileprocfs-attr-exec

The security information to be used on the processby a Linux security module (LSM) active on the systemafter a subsequentexec() call.The details of permissions required to read fromthis interface and hence obtain the security stateof the task identified is LSM dependent.A process cannot write to this interface unless itrefers to itself.The other details of permissions required to write tothis interface and hence change the security state ofthe task identified are LSM dependent.The format of the data used by this interface is LSMdependent.SELinux and AppArmor provide this interface.

Users:

SELinux user-spaceAppArmor user-space

Defined on fileprocfs-attr-prev

The security information used on the process bya Linux security module (LSM) active on the systemprior to the most recentexec() call.The details of permissions required to read fromthis interface is LSM dependent.A process cannot write to this interface unless itrefers to itself.The other details of permissions required to write tothis interface are LSM dependent.The format of the data used by this interface is LSMdependent.SELinux and AppArmor provide this interface.

Users:

SELinux user-spaceAppArmor user-space

00100000-ff709000 ---p 00000000 00:00 0          [rollup]Size:               1192 kBKernelPageSize:        4 kBMMUPageSize:           4 kBRss:                 884 kBPss:                 385 kBPss_Dirty:            68 kBPss_Anon:            301 kBPss_File:             80 kBPss_Shmem:             4 kBShared_Clean:        696 kBShared_Dirty:          0 kBPrivate_Clean:       120 kBPrivate_Dirty:        68 kBReferenced:          884 kBAnonymous:            68 kBLazyFree:              0 kBAnonHugePages:         0 kBShmemPmdMapped:        0 kBShared_Hugetlb:        0 kBPrivate_Hugetlb:       0 kBSwap:                  0 kBSwapPss:               0 kBLocked:              385 kB

Defined on filesysfs-bus-vfio-mdev

This is symbolic link pointing to supported type, <type-id>directory of which this mediated device is created.

Defined on filesysfs-bus-vfio-mdev

Writing ‘1’ to this file destroys the mediated device. Thevendor driver can fail theremove() callback if that deviceis active and the vendor driver doesn’t support hot unplug.Example:

# echo 1 > /sys/bus/mdev/devices/<UUID>/remove

Defined on filesysfs-bus-vfio-mdev

This directory contains list of directories of currentlysupported mediated device types and their details for<device>. Supported type attributes are defined by thevendor driver who registers with Mediated device framework.Each supported type is a directory whose name is createdby adding the device driver string as a prefix to thestring provided by the vendor driver.

Defined on filesysfs-bus-vfio-mdev

This directory gives details of supported type, like name,description, available_instances, device_api etc.‘device_api’ and ‘available_instances’ are mandatoryattributes to be provided by vendor driver. ‘name’,‘description’ and other vendor driver specific attributesare optional.

Defined on filesysfs-devices-vfio-dev

This directory is created when the device is bound to avfio driver. The layout under this directory matches whatexists for a standard ‘structdevice’. ‘X’ is a uniqueindex marking this device in vfio.

Defined on filesysfs-bus-iio-light-lm3533-als

Specifies the value of threshold that the device is comparingagainst for the events enabled byin_illuminance0_thresh_either_en (0..255), where Y in 0..3.

Note that threshY_falling must be less than or equal tothreshY_raising.

These thresholds correspond to the eight zone-boundaryregisters (boundaryY_{low,high}) and define the five lightzones.

Defined on filesysfs-bus-iio

Specifies the minimum quiet time in seconds between the twotaps of a double tap.

Defined on filesysfs-bus-iio

Lists all available delay values between two taps in the doubletap. Units in seconds.

Defined on filesysfs-bus-iio

Device generates an event on a single or double tap.

Defined on filesysfs-bus-iio

Specifies the timeout value in seconds for the tap detectorto not to look for another tap event after the event asoccurred. Basically the minimum quiet time between the twosingle-tap’s or two double-tap’s.

Defined on filesysfs-bus-iio

Specifies the threshold value that the device is comparingagainst to generate the tap gesture event. The lowerthreshold value increases the sensitivity of tap detection.Units and the exact meaning of value are device-specific.

Defined on filesysfs-bus-iio

Specifies the maximum time difference allowed between upperand lower peak of tap to consider it as the valid tap event.Units in seconds.

Defined on filesysfs-bus-iio

Lists all available time values between upper peak to lowerpeak. Units in seconds.

Defined on filesysfs-bus-iio

Lists all available tap reset timeout values. Units in seconds.

Defined on filesysfs-bus-iio

Lists all available threshold values which can be used tomodify the sensitivity of the tap detection.

Defined on filesysfs-bus-iio

Timeout value in seconds for tap gesture confirmation.

Defined on filesysfs-bus-iio

List of available timeout value for tap gesture confirmation.

Defined on filesysfs-bus-iio

Enable tap gesture confirmation with timeout.

Defined on filesysfs-bus-iio

Period of time (in seconds) for which the condition must bemet before an event is generated. If direction is notspecified then this period applies to both directions.

Defined on filesysfs-bus-iio

Specifies the value of threshold that the device is comparingagainst for the events enabled by<type>Y[_name]_thresh[_rising|falling]_en.

If separate attributes exist for the two directions, butdirection is not specified for this attribute, then a singlethreshold value applies to both directions.

The raw or input element of the name indicates whether thevalue is in raw device units or in processed units (as _rawand _input do on sysfs direct channel read attributes).

Defined on filesysfs-bus-iio

List of available periods for accelerometer event detection inseconds, expressed as:

• a range specified as “[min step max]”

Defined on filesysfs-bus-iio

The value to which the magnitude of the channel is compared. Ifnumber or direction is not specified, applies to all channels ofthis type.

Defined on filesysfs-bus-iio

Specifies the value of rate of change threshold that thedevice is comparing against for the events enabled by<type>[Y][_name]_roc[_rising|falling]_en.

If separate attributes exist for the two directions,but direction is not specified for this attribute,then a single threshold value applies to both directions.The raw or input element of the name indicates whether thevalue is in raw device units or in processed units (as _rawand _input do on sysfs direct channel read attributes).

Defined on filesysfs-bus-iio

Specifies the conversion factor from the standard unitsto device specific units used to set the event triggerthreshold.

Defined on filesysfs-bus-iio

If a high pass filter can be applied to the event generationthis property gives its 3db frequency in Hz.A value of zero disables the filter.

Defined on filesysfs-bus-iio

If a low pass filter can be applied to the event generationthis property gives its 3db frequency in Hz.A value of zero disables the filter.

Defined on filesysfs-bus-iio

List of available threshold values for acceleration eventgeneration. Applies to all event types on in_accel channels.Units after application of scale and offset are m/s^2.Expressed as:

• a range specified as “[min step max]”

Defined on filesysfs-bus-iio

Specifies the hysteresis of threshold that the device is comparingagainst for the events enabled by<type>Y[_name]_thresh[_(rising|falling)]_hysteresis.If separate attributes exist for the two directions, butdirection is not specified for this attribute, then a singlehysteresis value applies to both directions.

For falling events the hysteresis is added to the _value attribute forthis event to get the upper threshold for when the event goes back tonormal, for rising events the hysteresis is subtracted from the _valueattribute. E.g. if in_voltage0_raw_thresh_rising_value is set to 1200and in_voltage0_raw_thresh_rising_hysteresis is set to 50. The eventwill get activated once in_voltage0_raw goes above 1200 and will becomedeactivated again once the value falls below 1150.

Defined on filesysfs-bus-iio

Enables or disables activity events. Depending on directionan event is generated when sensor ENTERS or LEAVES a given state.

Defined on filesysfs-bus-iio

Confidence value (in units as percentage) to be usedfor deciding when an event should be generated. E.g forrunning: If the confidence value reported by the sensoris greater than in_activity_running_thresh_rising_valuethen the sensor ENTERS running state. Conversely, if theconfidence value reported by the sensor is lower thanin_activity_running_thresh_falling_value then the sensoris LEAVING running state.

Defined on filesysfs-bus-iio

Adaptive thresholds are similar to normal fixed thresholdsbut the value is expressed as an offset from a value whichprovides a low frequency approximation of the channel itself.Thus these detect if a rapid change occurs in the specifieddirection which crosses tracking value + offset.Tracking value calculation is devices specific.

Defined on filesysfs-bus-iio-light-lm3533-als

Get the hysteresis for thresholds Y, that is,threshY_hysteresis = threshY_raising - threshY_falling

Defined on filesysfs-bus-iio-light-lm3533-als

Event generated when channel passes one of the four thresholdsin each direction (rising|falling) and a zone change occurs.The corresponding light zone can be read fromin_illuminance0_zone.

Defined on filesysfs-bus-iio

Number of conditions that must occur, during a runningperiod, before an event is generated.

Defined on filesysfs-bus-iio

A running period of time (in seconds) for whichin_proximity_thresh_either_runningcount amount of conditionsmust occur before an event is generated. If direction is notspecified then this period applies to both directions.

Defined on filesysfs-bus-iio

Event generated when channel passes a threshold on the absolutechange in value. E.g. for steps: a step change event isgenerated each time the user takes N steps, where N is set usingin_steps_change_value.

Defined on filesysfs-bus-iio

Specifies the value of change threshold that thedevice is comparing against for the events enabled by<type>[Y][_name]_roc[_rising|falling|]_en. E.g. for steps:if set to 3, a step change event will be generated every 3steps.

Defined on filesysfs-bus-iio

Description of the scan element data storage within the bufferand hence the form in which it is read from user-space.Form is [be|le]:[s|u]bits/storagebits[>>shift].be or le specifies big or little endian. s or u specifies ifsigned (2’s complement) or unsigned. bits is the number of bitsof data and storagebits is the space (after padding) that itoccupies in the buffer. shift if specified, is the shift thatneeds to be applied prior to masking out unused bits. Somedevices put their data in the middle of the transferred elementswith additional information on both sides. Note that somedevices will have additional information in the unused bitsso to get a clean value, the bits value must be used to maskthe buffer output value appropriately. The storagebits valuealso specifies the data alignment. So s48/64>>2 will be asigned 48 bit integer stored in a 64 bit location aligned toa 64 bit boundary. To obtain the clean value, shift right 2and apply a mask to zero the top 16 bits of the result.For other storage combinations this attribute will be extendedappropriately.

Defined on filesysfs-bus-iio

Scan element control for triggered data capture.

Defined on filesysfs-bus-iio

A single positive integer specifying the position of thisscan element in the buffer. Note these are not dependent onwhat is enabled and may not be contiguous. Thus for user-spaceto establish the full layout these must be used in conjunctionwith all _en attributes to establish which channels are present,and the relevant _type attributes to establish the data storageformat.

Defined on filesysfs-bus-iio

Similar to in_accel_x_thresh[_rising|_falling]_en, but here themagnitude of the channel is compared to the threshold, not itssigned value.

Defined on filesysfs-bus-iio

Similar to in_accel_mag[_y][_rising|_falling]_en, but the eventvalue is relative to a reference magnitude. The reference magnitudeincludes the graviational acceleration.

Defined on filesysfs-bus-iio

The value to which the reference magnitude of the channel iscompared. If the axis is not specified, it applies to all channelsof this type.

Defined on filesysfs-bus-iio

Similar to in_accel_x_thresh[_rising|_falling]_en, but here themagnitude of the channel is compared to the adaptive threshold.

Defined on filesysfs-bus-iio

Event generated when channel passes a threshold on the rate ofchange (1st differential) in the specified (_rising|_falling)direction. If the direction is not specified, then either thedevice will report an event which ever direction a singlethreshold value is passed in (e.g.<type>[Y][_name]_<raw|input>_roc_value) or<type>[Y][_name]_<raw|input>_roc_rising_value and<type>[Y][_name]_<raw|input>_roc_falling_value may takedifferent values, but the device can only enable both rate ofchange thresholds or neither.

Note the driver will assume the last p events requested areto be enabled where p is however many it supports (which mayvary depending on the exact set requested. So if you want to besure you have set what you think you have, check the contents ofthese attributes after everything is configured. Drivers mayhave to buffer any parameters so that they are consistent whena given event type is enabled a future point (and not those forwhatever event was previously enabled).

Defined on filesysfs-bus-iio

Event generated when channel passes a threshold in the specified(_rising|_falling) direction. If the direction is not specified,then either the device will report an event which ever directiona single threshold value is passed in (e.g.<type>[Y][_name]_<raw|input>_thresh_value) or<type>[Y][_name]_<raw|input>_thresh_rising_value and<type>[Y][_name]_<raw|input>_thresh_falling_value may takedifferent values, but the device can only enable both thresholdsor neither.

Note the driver will assume the last p events requested areto be enabled where p is how many it supports (which may varydepending on the exact set requested. So if you want to besure you have set what you think you have, check the contents ofthese attributes after everything is configured. Drivers mayhave to buffer any parameters so that they are consistent whena given event type is enabled at a future point (and not those forwhatever event was previously enabled).

Defined on filesysfs-bus-iio

Specifies the chip power mode.low_noise: reduce noise level from ADC,low_power: enable low current consumption.For a list of available output power modes readin_accel_power_mode_available.

Defined on filesysfs-bus-iio

This attribute is used to read the confidence for an activityexpressed in units as percentage.

Defined on filesysfs-bus-iio

This attribute is used to read the amount of quadrature errorpresent in the device at a given time.

Defined on filesysfs-bus-iio

Value representing the user’s attention to the system expressedin units as percentage. This usually means if the user islooking at the screen or not.

Defined on filesysfs-bus-iio-cdc-ad7746

Write 1 to trigger a calibration of the calibbias orcalibscale. For calibscale, a full scale capacitance shouldbe connected to the capacitance input and acalibscale_calibration then started. For calibbias seethe device datasheet section on “capacitive system offsetcalibration”.

Defined on filesysfs-bus-iio

Raw differential capacitance measurement equivalent tochannel Y - channel Z where these channel numbers apply to thephysically equivalent inputs when non differential readings areseparately available. In differential only parts, then all thatis required is a consistent labeling. Units after applicationof scale and offset are nanofarads.

Defined on filesysfs-bus-iio

For differential channels, this an offset that is appliedequally to both inputs. As the reading is of the differencebetween the two inputs, this should not be applied to the _rawreading by userspace (unlike _offset) and unlike calibbiasit does not affect the differential value measured becausethe effect of _zeropoint cancels out across the two inputsthat make up the differential pair. It’s purpose is to bringthe individual signals, before the differential is measured,within the measurement range of the device. The naming ischosen because if the separate inputs that make thedifferential pair are drawn on a graph in their_raw units, this is the value that the zero point on themeasurement axis represents. It is expressed with thesame scaling as _raw.

Defined on filesysfs-bus-iio

This attribute is used to read the measured distance to an objector the distance covered by the user since the last reboot whileactivated. Units after application of scale are meters.

Defined on filesysfs-bus-iio

Activates a device feature that runs in firmware/hardware.E.g. for steps: the pedometer saves power while not used;when activated, it will count the steps taken by the user infirmware and export them through in_steps_input.

Defined on filesysfs-bus-iio

This attribute is used to read the energy value reported by thedevice (e.g.: human activity sensors report energy burnt by theuser). Units after application of scale are Joules.

Defined on filesysfs-bus-iio

Illuminance measurement, units after application of scaleand offset are lux.

Defined on filesysfs-bus-iio

Unit-less light intensity. Modifiers both and ir indicatethat measurements contain visible and infrared lightcomponents or just infrared light, respectively. Modifieruv indicates that measurements contain ultraviolet lightcomponents. Modifiers uva, uvb and duv indicate thatmeasurements contain A, B or deep (C) ultraviolet lightcomponents respectively.

Defined on filesysfs-bus-iio

This attribute is used to get/set the integration time inseconds. If shared across all channels of a given type,<type>_integration_time is used.

Defined on filesysfs-bus-iio

Proximity measurement indicating that someobject is near the sensor, usually by observingreflectivity of infrared or ultrasound emitted.

Often these sensors are unit less and as such conversionto SI units is not possible. Higher proximity measurementsindicate closer objects, and vice versa. Units afterapplication of scale and offset are meters.

Defined on filesysfs-bus-iio

The value of current sense resistor in Ohms.

Defined on filesysfs-bus-iio

Specifies the number of steps that must occur withinin_steps_filter_debounce_time for the pedometer to decide theconsumer is making steps.

Defined on filesysfs-bus-iio

Specifies number of seconds in which we compute the stepsthat occur in order to decide if the consumer is making steps.

Defined on filesysfs-bus-iio

This attribute is used to read the number of steps taken by the usersince the last reboot while activated.

Defined on filesysfs-bus-iio

UV light intensity index measuring the human skin’s response todifferent wavelength of sunlight weighted according to thestandardised CIE Erythemal Action Spectrum. UV index values rangefrom 0 (low) to >=11 (extreme).

Defined on filesysfs-bus-iio

This attribute is used to read the current speed value of theuser (which is the norm or magnitude of the velocity vector).Units after application of scale are m/s.

Defined on filesysfs-bus-iio

Number of seconds in which to compute speed.

Defined on filesysfs-bus-iio

Lists all available output power down modes.If Y is not present the mode is shared across all outputs.

Defined on filesysfs-bus-iio

If the type parameter can take one of a small set of values,this attribute lists them.

Defined on filesysfs-bus-iio

If a known or controllable high pass filter is appliedto the underlying data channel, then this parametergives the 3dB frequency of the filter in Hz.

Defined on filesysfs-bus-iio

If a known or controllable low pass filter is appliedto the underlying data channel, then this parametergives the 3dB frequency of the filter in Hz.

Defined on filesysfs-bus-iio

When adaptive thresholds are used, the tracking signalmay adjust too slowly to step changes in the raw signal.Thus these specify the time in seconds for which thedifference between the slow tracking signal and the rawsignal is allowed to remain out-of-range before a resetevent occurs in which the tracking signal is made equalto the raw signal, allowing slow tracking to resume and theadaptive threshold event detection to function as expected.

Defined on filesysfs-auxdisplay-linedisp

Read/write binary blob representing the ASCII-to-14-segmentdisplay conversion table used by the linedisp driver, as definedbystructseg14_conversion_map in <linux/map_to_14segment.h>.

Only visible on displays with 14-segment capability.

This attribute is not human-readable. Writes must match thestructsize exactly, else -EINVAL is returned; reads return theentire mapping as a binary blob.

This interface and its implementation match existing conventionsused by segment-mapped display drivers since 2005.

ABI note: This style of binary sysfs attributeis an exceptionto current “one value per file, text only” sysfs rules, forhistorical compatibility and driver uniformity. New drivers arediscouraged from introducing additional binary sysfs ABIs.

Reference interface guidance:- include/uapi/linux/map_to_14segment.h

Defined on filesysfs-auxdisplay-linedisp

Read/write binary blob representing the ASCII-to-7-segmentdisplay conversion table used by the linedisp driver, as definedbystructseg7_conversion_map in <linux/map_to_7segment.h>.

Only visible on displays with 7-segment capability.

This attribute is not human-readable. Writes must match thestructsize exactly, else -EINVAL is returned; reads return theentire mapping as a binary blob.

This interface and its implementation match existing conventionsused in segment-mapped display drivers since 2005.

ABI note: This style of binary sysfs attributeis an exceptionto current “one value per file, text only” sysfs rules, forhistorical compatibility and driver uniformity. New drivers arediscouraged from introducing additional binary sysfs ABIs.

Reference interface guidance:- include/uapi/linux/map_to_7segment.h

Defined on filesysfs-bus-vfio-mdev

Reading this attribute will show the number of mediateddevices of type <type-id> that can be created. This is areadonly file.

Users:

Userspace applications interested in creating mediateddevice of that type. Userspace application should checkthe number of available instances could be created beforecreating mediated device of this type.

Defined on filesysfs-bus-vfio-mdev

Writing UUID to this file will create mediated device oftype <type-id> for parent device <device>. This is awrite-only file.For example:

# echo "83b8f4f2-509f-382f-3c1e-e6bfe0fa1001" >       \     /sys/devices/foo/mdev_supported_types/foo-1/create

Defined on filesysfs-bus-vfio-mdev

Reading this attribute will show description of the type ofmediated device that will get created of type <type-id>.This is optional attribute. For example:“2 heads, 512M FB, 2560x1600 maximum resolution”

Users:

Userspace applications interested in knowing the details ofa particular <type-id> that can help in understanding thefeatures provided by that type of mediated device.

Defined on filesysfs-bus-vfio-mdev

Reading this attribute will show VFIO device API supportedby this type. For example, “vfio-pci” for a PCI device,“vfio-platform” for platform device.

Defined on filesysfs-bus-vfio-mdev

This directory contains symbolic links pointing to mdevdevices sysfs entries which are created of this <type-id>.

Defined on filesysfs-bus-vfio-mdev

Reading this attribute will show human readable name of themediated device that will get created of type <type-id>.This is optional attribute. For example: “Grid M60-0Q”

Users:

Userspace applications interested in knowing the name ofa particular <type-id> that can help in understanding thetype of mediated device.

Defined on filesysfs-auxdisplay-linedisp

Controls the text message displayed on character line displays.

Reading returns the current message with a trailing newline.Writing updates the displayed message. Messages longer than thedisplay width will automatically scroll. Trailing newlines ininput are automatically trimmed.

Writing an empty string clears the display.

Example:

echo “Hello World” > messagecat message # Returns “Hello Worldn”

Defined on filesysfs-auxdisplay-linedisp

Read-only attribute showing the character width capacity ofthe line display device. Messages longer than this will scroll.

Example:

cat num_chars # Returns “16n” for 16-char display

Defined on filesysfs-auxdisplay-linedisp

Controls the scrolling speed for messages longer than the displaywidth, specified in milliseconds per scroll step.

Setting to 0 disables scrolling. Default is 500ms.

Example:

echo “250” > scroll_step_ms # 4Hz scrollingcat scroll_step_ms # Returns “250n”

Defined on filesysfs-uevent

Enable passing additional variables for synthetic uevents thatare generated by writing /sys/.../uevent file.

Recognized extended format is:

ACTION [UUID [KEY=VALUE ...]

The ACTION is compulsory - it is the name of the ueventaction (add,change,remove). There is no changecompared to previous functionality here. The rest of theextended format is optional.

You need to pass UUID first before any KEY=VALUE pairs.The UUID must be inxxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxxformat where ‘x’ is a hex digit. The UUID is considered to bea transaction identifier so it’s possible to use the same UUIDvalue for one or more synthetic uevents in which case welogically group these uevents together for any userspacelisteners. The UUID value appears in uevent asSYNTH_UUID=xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx environmentvariable.

If UUID is not passed in, the generated synthetic uevent gainsSYNTH_UUID=0 environment variable automatically.

The KEY=VALUE pairs can contain alphanumeric characters only.

It’s possible to define zero or more pairs - each pair is thendelimited by a space character ‘ ‘. Each pair appears insynthetic uevent asSYNTH_ARG_KEY=VALUE. That means the KEYname gainsSYNTH_ARG_ prefix to avoid possible collisionswith existing variables.

Example of valid sequence written to the uevent file:

add fe4d7c9d-b8c6-4a70-9ef1-3d8a58d18eed A=1 B=abc

This generates synthetic uevent including these variables:

ACTION=addSYNTH_ARG_A=1SYNTH_ARG_B=abcSYNTH_UUID=fe4d7c9d-b8c6-4a70-9ef1-3d8a58d18eed

Users:

udev, userspace tools generating synthetic uevents

Defined on filesysfs-block-device

(RO) Indicates if the device supports the command durationlimits feature found in some ATA and SCSI devices.

Defined on filesysfs-block-device

(RW) Write to the file to turn on or off the SATA NCQ (nativecommand queueing) priority support. By default this feature isturned off. If the device does not support the SATA NCQpriority feature, writing “1” to this file results in an error(see ncq_prio_supported).

Defined on filesysfs-block-device

(RO) Indicates if the device supports the SATA NCQ (nativecommand queueing) priority feature.

Defined on filesysfs-block-device

(RW) This is the equivalent of the ncq_prio_enable attributefile for SATA devices connected to a SAS host-bus-adapter(HBA) implementing support for the SATA NCQ priority feature.This file does not exist if the HBA driver does not implementsupport for the SATA NCQ priority feature, regardless of thedevice support for this feature (see sas_ncq_prio_supported).

Defined on filesysfs-block-device

(RO) This is the equivalent of the ncq_prio_supported attributefile for SATA devices connected to a SAS host-bus-adapter(HBA) implementing support for the SATA NCQ priority feature.This file does not exist if the HBA driver does not implementsupport for the SATA NCQ priority feature, regardless of thedevice support for this feature.

Defined on filesysfs-block-device

(RW) Used by drivers which support software controlled activityLEDs.

It has the following valid values:

Note that the user must turn sw_activity OFF it they wish tocontrol the activity LED via the em_message file.

Defined on filesysfs-block-device

(RW) Hard disk shock protection

Writing an integer value to this file will take the heads of therespective drive off the platter and block all I/O operationsfor the specified number of milliseconds.

• If the device does not support the unload heads feature,access is denied with -EOPNOTSUPP.

• The maximal value accepted for a timeout is 30000milliseconds.

• A previously set timeout can be cancelled and disk can resumenormal operation immediately by specifying a timeout of 0.

• Some hard drives only comply with an earlier version of theATA standard, but support the unload feature nonetheless.There is no safe way Linux can detect these devices, so thisis not enabled by default. If it is known that your devicedoes support the unload feature, then you can tell the kernelto enable it by writing -1. It can be disabled again bywriting -2.

• Values below -2 are rejected with -EINVAL

For more information, seeHard disk shock protection

Defined on filesysfs-cfq-target-latency

The /sys/block/<device>/iosched/target_latency only existswhen the user sets cfq to /sys/block/<device>/scheduler.It contains an estimated latency time for the cfq. cfq willuse it to calculate the time slice used for every task.

Defined on filesysfs-block-bcache

Number of btree buckets/nodes that are currently cached inmemory; cache dynamically grows and shrinks in response tomemory pressure from the rest of the system.

Defined on filesysfs-block-bcache

For a cache, sum of all btree writes in human readable units.

Defined on filesysfs-block-bcache

For a cache, bucket size in human readable units, as set atcache creation time; should match the erase block size of theSSD for optimal performance.

Defined on filesysfs-block-bcache

Sum of all reads and writes that have bypassed the cache (dueto the sequential cutoff). Expressed as bytes in humanreadable units.

Defined on filesysfs-block-bcache

For a backing device that has cache, a symlink tothe bcache/ dir of that cache.

Defined on filesysfs-block-bcache

For backing devices: cache hits as a percentage.

Defined on filesysfs-block-bcache

For backing devices: integer number of full cache hits,counted per bio. A partial cache hit counts as a miss.

Defined on filesysfs-block-bcache

For backing devices: integer number of cache misses.

Defined on filesysfs-block-bcache

Writing to this file resets all the statistics for the device.

Defined on filesysfs-block-bcache

For a cache, the number of usable buckets.

Defined on filesysfs-block-bcache

For backing devices: Threshold past which sequential IO willskip the cache. Read and written as bytes in human readableunits (i.e. echo 10M > sequntial_cutoff).

Defined on filesysfs-block-bcache

For a cache, a boolean that allows synchronous mode to beswitched on and off. In synchronous mode all writes are orderedsuch that the cache can reliably recover from unclean shutdown;if disabled bcache will not generally wait for writes tocomplete but if the cache is not shut down cleanly all datawill be discarded from the cache. Should not be turned off withwriteback caching enabled.

Defined on filesysfs-block-bcache

For a cache, height of the btree excluding leaf nodes (i.e. aone node tree will have a depth of 0).

Defined on filesysfs-block-bcache

A write to this file causes the backing device or cache to beunregistered. If a backing device had dirty data in the cache,writeback mode is automatically disabled and all dirty data isflushed before the device is unregistered. Caches unregisterall associated backing devices before unregistering themselves.

Defined on filesysfs-block-bcache

For backing devices: When on, writeback caching is enabled andwrites will be buffered in the cache. When off, caching is inwritethrough mode; reads and writes will be added to thecache but no write buffering will take place.

Defined on filesysfs-block-bcache

For backing devices: In writeback mode, when dirty data iswritten to the cache and the cache held no dirty data for thatbacking device, writeback from cache to backing device startsafter this delay, expressed as an integer number of seconds.

Defined on filesysfs-block-bcache

For backing devices: If nonzero, writeback from cache tobacking device only takes place when more than this percentageof the cache is used, allowing more write coalescing to takeplace and reducing total number of writes sent to the backingdevice. Integer between 0 and 40.

Defined on filesysfs-block-bcache

For backing devices: when off, dirty data will not be writtenfrom the cache to the backing device. The cache will still beused to buffer writes until it is mostly full, at which pointwrites transparently revert to writethrough mode. Intended onlyfor benchmarking/testing.

Defined on filesysfs-block-bcache

For a cache, total amount of data in human readable unitswritten to the cache, excluding all metadata.

Defined on filesysfs-block-dm

Device-mapper device name.Read-only string containing mapped device name.

Users:

util-linux, device-mapper udev rules

Defined on filesysfs-block-dm

Allow control over how long a request that is areasonable merge candidate can be queued on the requestqueue. The resolution of this deadline is inmicroseconds (ranging from 1 to 100000 usecs).Setting this attribute to 0 (the default) will disablerequest-based DM’s merge heuristic and associated extraaccounting. This attribute is not applicable tobio-based DM devices so it will only ever report 0 forthem.

Defined on filesysfs-block-dm

Device-mapper device suspend state.Contains the value 1 while the device is suspended.Otherwise it contains 0. Read-only attribute.

Users:

util-linux, device-mapper udev rules

Defined on filesysfs-block-dm

Request-based Device-mapper blk-mq I/O path mode.Contains the value 1 if the device is using blk-mq.Otherwise it contains 0. Read-only attribute.

Defined on filesysfs-block-dm

Device-mapper device UUID.Read-only string containing DM-UUID or empty stringif DM-UUID is not set.

Users:

util-linux, device-mapper udev rules

Defined on filesysfs-block-aoe

(RO) Version of the firmware in the target.

Defined on filesysfs-block-aoe

(RO) The ethernet address of the remote Ata over Ethernet (AoE)device.

Defined on filesysfs-block-aoe

(RO) The names of the network interfaces on the localhost (commaseparated) through which we are communicating with the remoteAoE device.

Defined on filesysfs-block-aoe

(RO) The amount of user data transferred (in bytes) inside each AoEcommand on the network, network headers excluded.

Defined on filesysfs-block-aoe

(RO) Device status. The state attribute is “up” when the deviceis ready for I/O and “down” if detected but unusable. The“down,closewait” state shows that the device is still open andcannot come up again until it has been closed. The “up,kickme”state means that the driver wants to send more commands to thetarget but found out there were already the max number ofcommands waiting for a response. It will retry again after beingkicked by the periodic timer handler routine.

Defined on filesysfs-block-loop

(RO) Shows if the device is in autoclear mode or not ( “1” or“0”). Autoclear (if set) indicates that the loopback device willself-distruct after last close.

Defined on filesysfs-block-loop

(RO) The path of the backing file that the loop device maps itsdata blocks to.

Defined on filesysfs-block-loop

(RO) Shows if direct IO is being used to access backing file ornot (“1 or “0”).

Defined on filesysfs-block-loop

(RO) Start offset (in bytes).

Defined on filesysfs-block-loop

(RO) Shows if automatic partition scanning is enabled for thedevice or not (“1” or “0”). This can be requested individuallyper loop device during its setup by setting LO_FLAGS_PARTSCAN inin the ioctl request. By default, no partition tables arescanned.

Defined on filesysfs-block-loop

(RO) The size (in bytes) that the block device maps, startingfrom the offset.

Defined on filesysfs-block-rnbd

Contains the device access mode: ro, rw or migration.

Defined on filesysfs-block-rnbd

Contains the path that was passed as “device_path” to the map_deviceoperation.

Defined on filesysfs-block-rnbd

Contains the number of poll-mode queues

Defined on filesysfs-block-rnbd

Remap the disconnected device if the session is not destroyed yet.

Defined on filesysfs-block-rnbd

Write the number of sectors to change the size of the disk.

Defined on filesysfs-block-rnbd

RNBD uses RTRS session to transport the data between client andserver. The entry “session” contains the name of the session, thatwas used to establish the RTRS session. It’s the same name thatwas passed as server parameter to the map_device entry.

Defined on filesysfs-block-rnbd

The file contains the current state of the block device. The state filereturns “open” when the device is successfully mapped from the serverand accepting I/O requests. When the connection to the server getsdisconnected in case of an error (e.g. link failure), the state filereturns “closed” and all I/O requests submitted to it will fail with -EIO.

Defined on filesysfs-block-rnbd

To unmap a volume, “normal” or “force” has to be written to:/sys/block/rnbd<N>/rnbd/unmap_device

When “normal” is used, the operation will fail with EBUSY if any processis using the device. When “force” is used, the device is also unmappedwhen device is in use. All I/Os that are in progress will fail.

Example:

# echo "normal" > /sys/block/rnbd0/rnbd/unmap_device

Defined on filesysfs-block-rssd

This is a read-only file. Indicates the status of the device.

Defined on filesysfs-block-zram

The algorithm_params file is write-only and is used to setupcompression algorithm parameters.

Defined on filesysfs-block-zram

The backing_dev file is read-write and set up backingdevice for zram to write incompressible pages.For using, user should enable CONFIG_ZRAM_WRITEBACK.

Defined on filesysfs-block-zram

The bd_stat file is read-only and represents backing device’sstatistics (bd_count, bd_reads, bd_writes) in a formatsimilar to block layer statistics file format.

Defined on filesysfs-block-zram

The comp_algorithm file is read-write and lets to showavailable and selected compression algorithms, changecompression algorithm selection.

Defined on filesysfs-block-zram

The compact file is write-only and trigger compaction forallocator zrm uses. The allocator moves some objects so thatit could free fragment space.

Defined on filesysfs-block-zram

The debug_stat file is read-only and represents variousdevice’s debugging info useful for kernel developers. Itsformat is not documented intentionally and may changeanytime without any notice.

Defined on filesysfs-block-zram

The disksize file is read-write and specifies the disk sizewhich represents the limit on theuncompressed worth of datathat can be stored in this disk.Unit: bytes

Defined on filesysfs-block-zram

idle file is write-only and mark zram slot as idle.If system has mounted debugfs, user can see which slotsare idle via /sys/kernel/debug/zram/zram<id>/block_state

Defined on filesysfs-block-zram

The initstate file is read-only and shows the initializationstate of the device.

Defined on filesysfs-block-zram

The io_stat file is read-only and accumulates device’s I/Ostatistics not accounted by block layer. For example,failed_reads, failed_writes, etc. File format is similar toblock layer statistics file format.

Defined on filesysfs-block-zram

The mem_limit file is write-only and specifies the maximumamount of memory ZRAM can use to store the compressed data.The limit could be changed in run time and “0” means disablethe limit. No limit is the initial state. Unit: bytes

Defined on filesysfs-block-zram

The mem_used_max file is write-only and is used to resetthe counter of maximum memory zram have consumed to storecompressed data. For resetting the value, you should write“0”. Otherwise, you could see -EINVAL.Unit: bytes

Defined on filesysfs-block-zram

The mm_stat file is read-only and represents device’s mmstatistics (orig_data_size, compr_data_size, etc.) in a formatsimilar to block layer statistics file format.

Defined on filesysfs-block-zram

The recomp_algorithm file is read-write and allows to setor show secondary compression algorithms.

Defined on filesysfs-block-zram

The recompress file is write-only and triggers re-compressionwith secondary compression algorithms.

Defined on filesysfs-block-zram

The reset file is write-only and allows resetting thedevice. The reset operation frees all the memory associatedwith this device.

Defined on filesysfs-block-zram

The writeback file is write-only and trigger idle and/orhuge page writeback to backing device.

Defined on filesysfs-block-zram

The writeback_limit file is read-write and specifies the maximumamount of writeback ZRAM can do. The limit could be changedin run time.

Defined on filesysfs-block-zram

The writeback_limit_enable file is read-write and specifieseanbe of writeback_limit feature. “1” means eable the feature.No limit “0” is the initial state.

Defined on filesysfs-driver-intel-m10-bmc

Read only. Returns the hardware build version of IntelMAX10 BMC chip.Format: “0x%x”.

Defined on filesysfs-driver-intel-m10-bmc

Read only. Returns the firmware version of Intel MAX10BMC chip.Format: “0x%x”.

Defined on filesysfs-driver-intel-m10-bmc

Read only. Returns the first MAC address in a blockof sequential MAC addresses assigned to the boardthat is managed by the Intel MAX10 BMC. It is stored inFLASH storage and is mirrored in the MAX10 BMC registerspace.Format: “%02x:%02x:%02x:%02x:%02x:%02x”.

Defined on filesysfs-driver-intel-m10-bmc

Read only. Returns the number of sequential MACaddresses assigned to the board managed by the IntelMAX10 BMC. This value is stored in FLASH and is mirroredin the MAX10 BMC register space.Format: “%u”.

Defined on filesysfs-bus-acpi

This attribute contains the output of the device object’s_ADR control method, which is present for ACPI deviceobjects representing devices having standard enumerationalgorithms, such as PCI.

Defined on filesysfs-bus-acpi

This attribute contains the output of the device object’s_STR control method, if present.

Defined on filesysfs-bus-acpi

Writing 1 to this attribute will trigger hot removal ofthis device object. This file exists for every deviceobject that has _EJ0 method.

Defined on filesysfs-bus-acpi

This attribute indicates the hardware ID (_HID) of thedevice object. For example, PNP0103.This file is present for device objects having the _HIDcontrol method.

Defined on filesysfs-bus-acpi

(RO) Allows users to read the hardware version of non-PCIhardware, if the _HRV control method is present. It is mostlyuseful for non-PCI devices because lspci can list the hardwareversion for PCI devices.

Defined on filesysfs-bus-acpi

This attribute indicates the PNP IDs of the device object.That is acpi:HHHHHHHH:[CCCCCCC:]. Where each HHHHHHHH orCCCCCCCC contains device object’s PNPID (_HID or _CID).

Defined on filesysfs-bus-acpi

This attribute indicates the full path of ACPI namespaceobject associated with the device object. For example,_SB_.PCI0.

This file is not present for device objects representingfixed ACPI hardware features (like power and sleepbuttons).

Defined on filesysfs-bus-acpi

(RO) Returns the ACPI device status: enabled, disabled orfunctioning or present, if the method _STA is present.

The return value is a decimal integer representing the device’sstatus bitmap:

If bit [0] is clear, then bit 1 must also be clear (a devicethat is not present cannot be enabled).

Bit 0 can be clear (not present) with bit [3] set (device isfunctional). This case is used to indicate a valid device forwhich no device driver should be loaded.

More special cases are covered in the ACPI specification.

Defined on filesysfs-bus-acpi

This attribute contains the output of the device object’s_UID control method, if present.

Defined on filesysfs-driver-intel-rapid-start

An integer representing a set of wakeup events as follows:1: Wake to enter hibernation when the wakeup timer expires2: Wake to enter hibernation when the battery reaches acritical level

These values are ORed together. For example, a value of 3indicates that the system will wake to enter hibernation wheneither the wakeup timer expires or the battery reaches acritical level.

Defined on filesysfs-driver-intel-rapid-start

An integer representing the length of time the system willremain asleep before waking up to enter hibernation.This value is in minutes.

Defined on filesysfs-bus-amba

This file allows the driver for a device to be specified whichwill override standard OF, ACPI, ID table, and name matching.When specified, only a driver with a name matching the valuewritten to driver_override will have an opportunity to bind tothe device. The override is specified by writing a string to thedriver_override file (echo vfio-amba > driver_override) and maybe cleared with an empty string (echo > driver_override).This returns the device to standard matching rules binding.Writing to driver_override does not automatically unbind thedevice from its current driver or make any attempt toautomatically load the specified driver. If no driver with amatching name is currently loaded in the kernel, the device willnot bind to any driver. This also allows devices to opt-out ofdriver binding using a driver_override name such as “none”.Only a single driver may be specified in the override, there isno support for parsing delimiters.

Defined on filesysfs-bus-auxiliary

The /sys/devices/.../irqs directory contains a variable set offiles, with each file is named as irq number similar to PCI PFor VF’s irq number located in msi_irqs directory.These irq files are added and removed dynamically when an IRQis requested and freed respectively for the PCI SF.

Defined on filesysfs-driver-intel_sdsi

This directory contains interface files for accessing IntelOn Demand (formerly Software Defined Silicon or SDSi) featureson a CPU. X represents the socket instance (though not thesocket ID). The socket ID is determined by reading theregisters file and decoding it per the specification.

Some files communicate with On Demand hardware through amailbox. Should the operation fail, one of the following errorcodes may be returned:

Defined on filesysfs-driver-intel_sdsi

(RO) The GUID for the registers file. The GUID identifiesthe layout of the registers file in this directory.Information about the register layouts for a particular GUIDis available athttp://github.com/intel/intel-sdsi

Defined on filesysfs-driver-intel_sdsi

(RO) Used to read back the current meter certificate for the CPUfrom Intel On Demand hardware. The meter certificate containsutilization metrics of On Demand enabled features. Mailboxcommand.

Defined on filesysfs-driver-intel_sdsi

(WO) Used to write an Authentication Key Certificate (AKC) tothe On Demand NVRAM for the CPU. The AKC is used to authenticatea Capability Activation Payload. Mailbox command.

Defined on filesysfs-driver-intel_sdsi

(WO) Used to write a Capability Activation Payload (CAP) to theOn Demand NVRAM for the CPU. CAPs are used to activate a givenCPU feature. A CAP is validated by On Demand hardware using apreviously provisioned AKC file. Upon successful authentication,the CPU configuration is updated. A cold reboot is required tofully activate the feature. Mailbox command.

Defined on filesysfs-driver-intel_sdsi

(RO) Contains information needed by applications to provisiona CPU and monitor status information. The layout of this fileis determined by the GUID in this directory. Information aboutthe layout for a particular GUID is available athttp://github.com/intel/intel-sdsi

Defined on filesysfs-driver-intel_sdsi

(RO) Used to read back the current state certificate for the CPUfrom On Demand hardware. The state certificate containsinformation about the current licenses on the CPU. Mailboxcommand.

Defined on filesysfs-bus-bcma

Each BCMA core is identified by few fields, including class itbelongs to. See include/linux/bcma/bcma.h for possible values.

Defined on filesysfs-bus-bcma

There are a few types of BCMA cores, they can be identified byid field.

Defined on filesysfs-bus-bcma

Each BCMA core has its manufacturer id. Seeinclude/linux/bcma/bcma.h for possible values.

Defined on filesysfs-bus-bcma

BCMA cores of the same type can still slightly differ dependingon their revision. Use it for detailed programming.

Defined on filesysfs-bus-cdx

This file contains the class of the CDX device, in hexadecimal.Class is 24 bit identifier specifies the functionality of the device.

Defined on filesysfs-bus-cdx

Device ID for this CDX device, in hexadecimal. Device ID is16 bit identifier to identify a device type within the rangeof a device manufacturer.Combination of Vendor ID and Device ID identifies a device.

Defined on filesysfs-bus-cdx

CDX bus should be disabled before updating the devices in FPGA.Writing n/0/off will attempt to disable the CDX bus and.writing y/1/on will attempt to enable the CDX bus. Reading this filegives the current state of the bus, 1 for enabled and 0 for disabled.

For example:

# echo 1 > /sys/bus/cdx/.../enable

Defined on filesysfs-bus-cdx

This attribute indicates the CDX ID of the device.That is in the format:cdx:vXXXXdXXXXsvXXXXsdXXXXcXXXXXX,where:

• vXXXX contains the vendor ID;

• dXXXX contains the device ID;

• svXXXX contains the subsystem vendor ID;

• sdXXXX contains the subsystem device ID;

• cXXXXXX contains the device class.

Defined on filesysfs-bus-cdx

Writing y/1/on to this file removes the correspondingdevice from the CDX bus. If the device is to be reconfiguredreconfigured in the Hardware, the device can be removed, sothat the device driver does not access the device while it isbeing reconfigured.

For example:

# echo 1 > /sys/bus/cdx/devices/.../remove

Defined on filesysfs-bus-cdx

Writing y/1/on to this file resets the CDX device or all deviceson the bus. On resetting the device, the corresponding driver isnotified twice, once before the device is being reset, and againafter the reset has been complete.

For example:

# echo 1 > /sys/bus/cdx/.../reset

Defined on filesysfs-bus-cdx

The resource binary file contains the content of the memoryregions. These files can be m’maped from userspace.

Defined on filesysfs-bus-cdx

This file contains the revision field of the CDX device, in hexadecimal.Revision is 8 bit revision identifier of the device.

Defined on filesysfs-bus-cdx

Subsystem Device ID for this CDX device, in hexadecimalSubsystem Device ID is 16 bit identifier specific to thecard manufacturer.

Defined on filesysfs-bus-cdx

Subsystem Vendor ID for this CDX device, in hexadecimal.Subsystem Vendor ID is 16 bit identifier specific to thecard manufacturer.

Defined on filesysfs-bus-cdx

Vendor ID for this CDX device, in hexadecimal. Vendor ID is16 bit identifier which is specific to the device manufacturer.Combination of Vendor ID and Device ID identifies a device.

Defined on filesysfs-bus-cdx

Writing y/1/on to this file will cause rescan of the busand devices on the CDX bus. Any new devices are scanned andadded to the list of Linux devices and any devices removed arealso deleted from Linux.

For example:

# echo 1 > /sys/bus/cdx/rescan

Defined on filesysfs-bus-coreboot

The coreboot bus provides a variety of virtual devices used toaccess data structures created by the Coreboot BIOS.

Defined on filesysfs-bus-coreboot

CBMEM is a downwards-growing memory region created by Coreboot,and contains tagged data structures to be shared with payloadsin the boot process and the OS. Each CBMEM entry is given adirectory in /sys/bus/coreboot/devices based on its id.A list of ids known to Coreboot can be found in the corebootsource tree atsrc/commonlib/bsd/include/commonlib/bsd/cbmem_id.h.

Defined on filesysfs-bus-coreboot

This is the physical memory address that the CBMEM entry’s databegins at, in hexadecimal (e.g.,0x76ffe000).

Defined on filesysfs-bus-coreboot

A file exposing read/write access to the entry’s data. Notethat this file does not support mmap(), as corebootdoes not guarantee that the data will be page-aligned.

The mode of this file is 0600. While there shouldn’t beanything security-sensitive contained in CBMEM, read accessrequires root privileges given this is exposing a small subsetof physical memory.

Defined on filesysfs-bus-coreboot

This is the size of the CBMEM entry’s data, in hexadecimal(e.g.,0x1234).

Defined on filesysfs-bus-coresight-devices-cti

(Write) Deactivate a single channel.

Defined on filesysfs-bus-coresight-devices-cti

(Read) show channels with no attached trigger signals.

Defined on filesysfs-bus-coresight-devices-cti

(Write) Disable CTIGATE for single channel.

Defined on filesysfs-bus-coresight-devices-cti

(RW) Enable CTIGATE for single channel (Write) or list enabledchannels through the gate (R).

Defined on filesysfs-bus-coresight-devices-cti

(Read) show channels with at least one attached trigger signal.

Defined on filesysfs-bus-coresight-devices-cti

(Write) Pulse a single channel - activate for a single clock cycle.

Defined on filesysfs-bus-coresight-devices-cti

(Write) Activate a single channel.

Defined on filesysfs-bus-coresight-devices-cti

(Read) Read to see input triggers connected to selected viewchannel.

Defined on filesysfs-bus-coresight-devices-cti

(Read) Read to see output triggers connected to selected viewchannel.

Defined on filesysfs-bus-coresight-devices-cti

(Write) Clear all channel / trigger programming.

Defined on filesysfs-bus-coresight-devices-cti

(RW) Write channel number to select a channel to view, read tosee selected channel number.

Defined on filesysfs-bus-coresight-devices-cti

(RW) Enable or disable trigger output signal filtering.

Defined on filesysfs-bus-coresight-devices-cti

(Write) Attach a CTI input trigger to a CTM channel.

Defined on filesysfs-bus-coresight-devices-cti

(Write) Detach a CTI input trigger from a CTM channel.

Defined on filesysfs-bus-coresight-devices-cti

(Write) Attach a CTI output trigger to a CTM channel.

Defined on filesysfs-bus-coresight-devices-cti

(Write) Detach a CTI output trigger from a CTM channel.

Defined on filesysfs-bus-coresight-devices-cti

(Read) List of output triggers filtered across all connections.

Defined on filesysfs-bus-coresight-devices-cti

(Read) Display the associated CTM ID

Defined on filesysfs-bus-coresight-devices-cti

(RW) Enable/Disable the CTI hardware.

Defined on filesysfs-bus-coresight-devices-cti

(Read) Show hardware context information of device.

Defined on filesysfs-bus-coresight-devices-cti

(Read) Number of devices connected to triggers on this CTI

Defined on filesysfs-bus-coresight-devices-cti

(Read) Indicate if the CTI hardware is powered.

Defined on filesysfs-bus-coresight-devices-cti

(Write) Write APPCLEAR register to deactivate channel.

Defined on filesysfs-bus-coresight-devices-cti

(Write) Write APPPULSE to pulse a channel active for one clockcycle.

Defined on filesysfs-bus-coresight-devices-cti

(RW) Set CTIAPPSET register to activate channel. Read back todetermine current value of register.

Defined on filesysfs-bus-coresight-devices-cti

(RW) Read or write ASICCTL register.

Defined on filesysfs-bus-coresight-devices-cti

(Read) Read current status of channel inputs.

Defined on filesysfs-bus-coresight-devices-cti

(Read) read current status of channel outputs.

Defined on filesysfs-bus-coresight-devices-cti

(RW) Read or write CTIGATE register.

Defined on filesysfs-bus-coresight-devices-cti

(RW) Read or write the CTIINEN register selected by inout_sel.

Defined on filesysfs-bus-coresight-devices-cti

(RW) Select the index for inen and outen registers.

Defined on filesysfs-bus-coresight-devices-cti

(Write) Write the INTACK register.

Defined on filesysfs-bus-coresight-devices-cti

(RW) Read or write the CTIOUTEN register selected by inout_sel.

Defined on filesysfs-bus-coresight-devices-cti

(Read) read current status of input trigger signals

Defined on filesysfs-bus-coresight-devices-cti

(Read) read current status of output trigger signals.

Defined on filesysfs-bus-coresight-devices-cti

(Read) Input trigger signals from connected device <N>

Defined on filesysfs-bus-coresight-devices-cti

(Read) Functional types for the input trigger signalsfrom connected device <N>

Defined on filesysfs-bus-coresight-devices-cti

(Read) Name of connected device <N>

Defined on filesysfs-bus-coresight-devices-cti

(Read) Output trigger signals to connected device <N>

Defined on filesysfs-bus-coresight-devices-cti

(Read) Functional types for the output trigger signalsto connected device <N>

Defined on filesysfs-bus-coresight-devices-etm3x

(RW) Used in conjunction with @addr_idx. Specifiescharacteristics about the address comparator being configure,for example the access type, the kind of instruction to trace,processor context ID to trigger on, etc. Individual fields inthe access type register may vary on the version of the traceentity.

Defined on filesysfs-bus-coresight-devices-etm3x

Select which address comparator or pair (of comparators) towork with.

Defined on filesysfs-bus-coresight-devices-etm3x

(RW) Used in conjunction with @addr_idx. Specifies the range ofaddresses to trigger on. Inclusion or exclusion is specifiedin the corresponding access type register.

Defined on filesysfs-bus-coresight-devices-etm3x

(RW) Used in conjunction with @addr_idx. Specifies the singleaddress to trigger on, highly influenced by the configurationoptions of the corresponding access type register.

Defined on filesysfs-bus-coresight-devices-etm3x

(RW) Used in conjunction with @addr_idx. Specifies the singleaddress to start tracing on, highly influenced by theconfiguration options of the corresponding access type register.

Defined on filesysfs-bus-coresight-devices-etm3x

(RW) Used in conjunction with @addr_idx. Specifies the singleaddress to stop tracing on, highly influenced by theconfiguration options of the corresponding access type register.

Defined on filesysfs-bus-coresight-devices-etm3x

(RW) Used in conjunction with cntr_idx, give access to thecounter event register.

Defined on filesysfs-bus-coresight-devices-etm3x

(RW) Specifies the counter to work on.

Defined on filesysfs-bus-coresight-devices-etm3x

(RW) Used in conjunction with cntr_idx, give access to thecounter reload event register.

Defined on filesysfs-bus-coresight-devices-etm3x

(RW) Used in conjunction with cntr_idx, give access to thecounter reload value register.

Defined on filesysfs-bus-coresight-devices-etm3x

(RW) Used in conjunction with cntr_idx, give access to thecounter value register.

Defined on filesysfs-bus-coresight-devices-etm3x

(RO) Holds the cpu number this tracer is affined to.

Defined on filesysfs-bus-coresight-devices-etm3x

(RW) Specifies the index of the context ID register to beselected.

Defined on filesysfs-bus-coresight-devices-etm3x

(RW) Mask to apply to all the context ID comparator.

Defined on filesysfs-bus-coresight-devices-etm3x

(RW) Used with the ctxid_idx, specify with context ID to triggeron.

Defined on filesysfs-bus-coresight-devices-etm3x

(Read) Holds the current state of the sequencer.

Defined on filesysfs-bus-coresight-devices-etm3x

(RW) Defines which event triggers a trace.

Defined on filesysfs-bus-coresight-devices-etm3x

(RW) Enable/disable tracing on this specific trace entiry.Enabling a source implies the source has been configuredproperly and a sink has been identidifed for it. The pathof coresight components linking the source to the sink isconfigured and managed automatically by the coresight framework.

Defined on filesysfs-bus-coresight-devices-etm3x

(RW) Gives access to the ETM status register, which holdsprogramming information and status on certains events.

Defined on filesysfs-bus-coresight-devices-etm3x

(RW) Number of byte left in the fifo before considering it full.Depending on the tracer’s version, can also hold threshold fordata suppression.

Defined on filesysfs-bus-coresight-devices-etm3x

(Read) Show hardware context information of device.

Defined on filesysfs-bus-coresight-devices-etm3x

(RO) Print the content of the ETM Configuration Code Extensionregister (0x1e8). The value is read directly from the HW.

Defined on filesysfs-bus-coresight-devices-etm3x

(RO) Print the content of the ETM Configuration Code register(0x004). The value is read directly from the HW.

Defined on filesysfs-bus-coresight-devices-etm3x

(RO) Print the content of the ETM Main Control register (0x000).The value is read directly from the HW.

Defined on filesysfs-bus-coresight-devices-etm3x

(RO) Print the content of the ETM ID register (0x1e4). Thevalue is read directly from the HW.

Defined on filesysfs-bus-coresight-devices-etm3x

(RO) Print the content of the ETM System Configurationregister (0x014). The value is read directly from the HW.

Defined on filesysfs-bus-coresight-devices-etm3x

(RO) Print the content of the ETM Enable Control #1register (0x024). The value is read directly from the HW.

Defined on filesysfs-bus-coresight-devices-etm3x

(RO) Print the content of the ETM Enable Control #2register (0x01c). The value is read directly from the HW.

Defined on filesysfs-bus-coresight-devices-etm3x

(RO) Print the content of the ETM Trace Enable Event register(0x020). The value is read directly from the HW.

Defined on filesysfs-bus-coresight-devices-etm3x

(RO) Print the content of the ETM Trace ID register (0x200).The value is read directly from the HW.

Defined on filesysfs-bus-coresight-devices-etm3x

(RO) Print the content of the ETM Trace Start/Stop Controlregister (0x018). The value is read directly from the HW.

Defined on filesysfs-bus-coresight-devices-etm3x

(RW) Interface with the driver’s ‘mode’ field, controllingvarious aspect of the trace entity such as time stamping,context ID size and cycle accurate tracing. Driver specificand bound to change depending on the driver.

Defined on filesysfs-bus-coresight-devices-etm3x

(Read) Provides the number of address comparators pairs accessibleon a trace unit, as specified by bit 3:0 of register ETMCCR.

Defined on filesysfs-bus-coresight-devices-etm3x