0001 What: /sys/bus/usb/devices/<INTERFACE>/authorized
0002 Date: August 2015
0003 Description:
0004 This allows to authorize (1) or deauthorize (0)
0005 individual interfaces instead a whole device
0006 in contrast to the device authorization.
0007 If a deauthorized interface will be authorized
0008 so the driver probing must be triggered manually
0009 by writing INTERFACE to /sys/bus/usb/drivers_probe
0010 This allows to avoid side-effects with drivers
0011 that need multiple interfaces.
0012
0013 A deauthorized interface cannot be probed or claimed.
0014
0015 What: /sys/bus/usb/devices/usbX/interface_authorized_default
0016 Date: August 2015
0017 Description:
0018 This is used as value that determines if interfaces
0019 would be authorized by default.
0020 The value can be 1 or 0. It's by default 1.
0021
0022 What: /sys/bus/usb/device/.../authorized
0023 Date: July 2008
0024 KernelVersion: 2.6.26
0025 Contact: David Vrabel <david.vrabel@csr.com>
0026 Description:
0027 Authorized devices are available for use by device
0028 drivers, non-authorized one are not. By default, wired
0029 USB devices are authorized.
0030
0031 Certified Wireless USB devices are not authorized
0032 initially and should be (by writing 1) after the
0033 device has been authenticated.
0034
0035 What: /sys/bus/usb/device/.../wusb_cdid
0036 Date: July 2008
0037 KernelVersion: 2.6.27
0038 Contact: David Vrabel <david.vrabel@csr.com>
0039 Description:
0040 For Certified Wireless USB devices only.
0041
0042 A devices's CDID, as 16 space-separated hex octets.
0043
0044 What: /sys/bus/usb/device/.../wusb_ck
0045 Date: July 2008
0046 KernelVersion: 2.6.27
0047 Contact: David Vrabel <david.vrabel@csr.com>
0048 Description:
0049 For Certified Wireless USB devices only.
0050
0051 Write the device's connection key (CK) to start the
0052 authentication of the device. The CK is 16
0053 space-separated hex octets.
0054
0055 What: /sys/bus/usb/device/.../wusb_disconnect
0056 Date: July 2008
0057 KernelVersion: 2.6.27
0058 Contact: David Vrabel <david.vrabel@csr.com>
0059 Description:
0060 For Certified Wireless USB devices only.
0061
0062 Write a 1 to force the device to disconnect
0063 (equivalent to unplugging a wired USB device).
0064
0065 What: /sys/bus/usb/drivers/.../new_id
0066 Date: October 2011
0067 Contact: linux-usb@vger.kernel.org
0068 Description:
0069 Writing a device ID to this file will attempt to
0070 dynamically add a new device ID to a USB device driver.
0071 This may allow the driver to support more hardware than
0072 was included in the driver's static device ID support
0073 table at compile time. The format for the device ID is:
0074 idVendor idProduct bInterfaceClass RefIdVendor RefIdProduct
0075 The vendor ID and device ID fields are required, the
0076 rest is optional. The `Ref*` tuple can be used to tell the
0077 driver to use the same driver_data for the new device as
0078 it is used for the reference device.
0079 Upon successfully adding an ID, the driver will probe
0080 for the device and attempt to bind to it. For example::
0081
0082 # echo "8086 10f5" > /sys/bus/usb/drivers/foo/new_id
0083
0084 Here add a new device (0458:7045) using driver_data from
0085 an already supported device (0458:704c)::
0086
0087 # echo "0458 7045 0 0458 704c" > /sys/bus/usb/drivers/foo/new_id
0088
0089 Reading from this file will list all dynamically added
0090 device IDs in the same format, with one entry per
0091 line. For example::
0092
0093 # cat /sys/bus/usb/drivers/foo/new_id
0094 8086 10f5
0095 dead beef 06
0096 f00d cafe
0097
0098 The list will be truncated at PAGE_SIZE bytes due to
0099 sysfs restrictions.
0100
0101 What: /sys/bus/usb-serial/drivers/.../new_id
0102 Date: October 2011
0103 Contact: linux-usb@vger.kernel.org
0104 Description:
0105 For serial USB drivers, this attribute appears under the
0106 extra bus folder "usb-serial" in sysfs; apart from that
0107 difference, all descriptions from the entry
0108 "/sys/bus/usb/drivers/.../new_id" apply.
0109
0110 What: /sys/bus/usb/drivers/.../remove_id
0111 Date: November 2009
0112 Contact: CHENG Renquan <rqcheng@smu.edu.sg>
0113 Description:
0114 Writing a device ID to this file will remove an ID
0115 that was dynamically added via the new_id sysfs entry.
0116 The format for the device ID is:
0117 idVendor idProduct. After successfully
0118 removing an ID, the driver will no longer support the
0119 device. This is useful to ensure auto probing won't
0120 match the driver to the device. For example:
0121 # echo "046d c315" > /sys/bus/usb/drivers/foo/remove_id
0122
0123 Reading from this file will list the dynamically added
0124 device IDs, exactly like reading from the entry
0125 "/sys/bus/usb/drivers/.../new_id"
0126
0127 What: /sys/bus/usb/devices/.../power/usb2_hardware_lpm
0128 Date: September 2011
0129 Contact: Andiry Xu <andiry.xu@amd.com>
0130 Description:
0131 If CONFIG_PM is set and a USB 2.0 lpm-capable device is plugged
0132 in to a xHCI host which support link PM, it will perform a LPM
0133 test; if the test is passed and host supports USB2 hardware LPM
0134 (xHCI 1.0 feature), USB2 hardware LPM will be enabled for the
0135 device and the USB device directory will contain a file named
0136 power/usb2_hardware_lpm. The file holds a string value (enable
0137 or disable) indicating whether or not USB2 hardware LPM is
0138 enabled for the device. Developer can write y/Y/1 or n/N/0 to
0139 the file to enable/disable the feature.
0140
0141 What: /sys/bus/usb/devices/.../power/usb3_hardware_lpm_u1
0142 /sys/bus/usb/devices/.../power/usb3_hardware_lpm_u2
0143 Date: November 2015
0144 Contact: Kevin Strasser <kevin.strasser@linux.intel.com>
0145 Lu Baolu <baolu.lu@linux.intel.com>
0146 Description:
0147 If CONFIG_PM is set and a USB 3.0 lpm-capable device is plugged
0148 in to a xHCI host which supports link PM, it will check if U1
0149 and U2 exit latencies have been set in the BOS descriptor; if
0150 the check is passed and the host supports USB3 hardware LPM,
0151 USB3 hardware LPM will be enabled for the device and the USB
0152 device directory will contain two files named
0153 power/usb3_hardware_lpm_u1 and power/usb3_hardware_lpm_u2. These
0154 files hold a string value (enable or disable) indicating whether
0155 or not USB3 hardware LPM U1 or U2 is enabled for the device.
0156
0157 What: /sys/bus/usb/devices/.../ltm_capable
0158 Date: July 2012
0159 Contact: Sarah Sharp <sarah.a.sharp@linux.intel.com>
0160 Description:
0161 USB 3.0 devices may optionally support Latency Tolerance
0162 Messaging (LTM). They indicate their support by setting a bit
0163 in the bmAttributes field of their SuperSpeed BOS descriptors.
0164 If that bit is set for the device, ltm_capable will read "yes".
0165 If the device doesn't support LTM, the file will read "no".
0166 The file will be present for all speeds of USB devices, and will
0167 always read "no" for USB 1.1 and USB 2.0 devices.
0168
0169 What: /sys/bus/usb/devices/.../<hub_interface>/port<X>
0170 Date: August 2012
0171 Contact: Lan Tianyu <tianyu.lan@intel.com>
0172 Description:
0173 The /sys/bus/usb/devices/.../<hub_interface>/port<X>
0174 is usb port device's sysfs directory.
0175
0176 What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/connect_type
0177 Date: January 2013
0178 Contact: Lan Tianyu <tianyu.lan@intel.com>
0179 Description:
0180 Some platforms provide usb port connect types through ACPI.
0181 This attribute is to expose these information to user space.
0182 The file will read "hotplug", "hardwired" and "not used" if the
0183 information is available, and "unknown" otherwise.
0184
0185 What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/location
0186 Date: October 2018
0187 Contact: Bjørn Mork <bjorn@mork.no>
0188 Description:
0189 Some platforms provide usb port physical location through
0190 firmware. This is used by the kernel to pair up logical ports
0191 mapping to the same physical connector. The attribute exposes the
0192 raw location value as a hex integer.
0193
0194
0195 What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/quirks
0196 Date: May 2018
0197 Contact: Nicolas Boichat <drinkcat@chromium.org>
0198 Description:
0199 In some cases, we care about time-to-active for devices
0200 connected on a specific port (e.g. non-standard USB port like
0201 pogo pins), where the device to be connected is known in
0202 advance, and behaves well according to the specification.
0203 This attribute is a bit-field that controls the behavior of
0204 a specific port:
0205
0206 - Bit 0 of this field selects the "old" enumeration scheme,
0207 as it is considerably faster (it only causes one USB reset
0208 instead of 2).
0209
0210 The old enumeration scheme can also be selected globally
0211 using /sys/module/usbcore/parameters/old_scheme_first, but
0212 it is often not desirable as the new scheme was introduced to
0213 increase compatibility with more devices.
0214 - Bit 1 reduces TRSTRCY to the 10 ms that are required by the
0215 USB 2.0 specification, instead of the 50 ms that are normally
0216 used to help make enumeration work better on some high speed
0217 devices.
0218
0219 What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/over_current_count
0220 Date: February 2018
0221 Contact: Richard Leitner <richard.leitner@skidata.com>
0222 Description:
0223 Most hubs are able to detect over-current situations on their
0224 ports and report them to the kernel. This attribute is to expose
0225 the number of over-current situation occurred on a specific port
0226 to user space. This file will contain an unsigned 32 bit value
0227 which wraps to 0 after its maximum is reached. This file supports
0228 poll() for monitoring changes to this value in user space.
0229
0230 Any time this value changes the corresponding hub device will send a
0231 udev event with the following attributes::
0232
0233 OVER_CURRENT_PORT=/sys/bus/usb/devices/.../<hub_interface>/port<X>
0234 OVER_CURRENT_COUNT=[current value of this sysfs attribute]
0235
0236 What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/usb3_lpm_permit
0237 Date: November 2015
0238 Contact: Lu Baolu <baolu.lu@linux.intel.com>
0239 Description:
0240 Some USB3.0 devices are not friendly to USB3 LPM. usb3_lpm_permit
0241 attribute allows enabling/disabling usb3 lpm of a port. It takes
0242 effect both before and after a usb device is enumerated. Supported
0243 values are "0" if both u1 and u2 are NOT permitted, "u1" if only u1
0244 is permitted, "u2" if only u2 is permitted, "u1_u2" if both u1 and
0245 u2 are permitted.
0246
0247 What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/connector
0248 Date: December 2021
0249 Contact: Heikki Krogerus <heikki.krogerus@linux.intel.com>
0250 Description:
0251 Link to the USB Type-C connector when available. This link is
0252 only created when USB Type-C Connector Class is enabled, and
0253 only if the system firmware is capable of describing the
0254 connection between a port and its connector.
0255
0256 What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/disable
0257 Date: June 2022
0258 Contact: Michael Grzeschik <m.grzeschik@pengutronix.de>
0259 Description:
0260 This file controls the state of a USB port, including
0261 Vbus power output (but only on hubs that support
0262 power switching -- most hubs don't support it). If
0263 a port is disabled, the port is unusable: Devices
0264 attached to the port will not be detected, initialized,
0265 or enumerated.
0266
0267 What: /sys/bus/usb/devices/.../power/usb2_lpm_l1_timeout
0268 Date: May 2013
0269 Contact: Mathias Nyman <mathias.nyman@linux.intel.com>
0270 Description:
0271 USB 2.0 devices may support hardware link power management (LPM)
0272 L1 sleep state. The usb2_lpm_l1_timeout attribute allows
0273 tuning the timeout for L1 inactivity timer (LPM timer), e.g.
0274 needed inactivity time before host requests the device to go to L1 sleep.
0275 Useful for power management tuning.
0276 Supported values are 0 - 65535 microseconds.
0277
0278 What: /sys/bus/usb/devices/.../power/usb2_lpm_besl
0279 Date: May 2013
0280 Contact: Mathias Nyman <mathias.nyman@linux.intel.com>
0281 Description:
0282 USB 2.0 devices that support hardware link power management (LPM)
0283 L1 sleep state now use a best effort service latency value (BESL) to
0284 indicate the best effort to resumption of service to the device after the
0285 initiation of the resume event.
0286 If the device does not have a preferred besl value then the host can select
0287 one instead. This usb2_lpm_besl attribute allows to tune the host selected besl
0288 value in order to tune power saving and service latency.
0289
0290 Supported values are 0 - 15.
0291 More information on how besl values map to microseconds can be found in
0292 USB 2.0 ECN Errata for Link Power Management, section 4.10)
0293
0294 What: /sys/bus/usb/devices/.../rx_lanes
0295 Date: March 2018
0296 Contact: Mathias Nyman <mathias.nyman@linux.intel.com>
0297 Description:
0298 Number of rx lanes the device is using.
0299 USB 3.2 adds Dual-lane support, 2 rx and 2 tx lanes over Type-C.
0300 Inter-Chip SSIC devices support asymmetric lanes up to 4 lanes per
0301 direction. Devices before USB 3.2 are single lane (rx_lanes = 1)
0302
0303 What: /sys/bus/usb/devices/.../tx_lanes
0304 Date: March 2018
0305 Contact: Mathias Nyman <mathias.nyman@linux.intel.com>
0306 Description:
0307 Number of tx lanes the device is using.
0308 USB 3.2 adds Dual-lane support, 2 rx and 2 tx -lanes over Type-C.
0309 Inter-Chip SSIC devices support asymmetric lanes up to 4 lanes per
0310 direction. Devices before USB 3.2 are single lane (tx_lanes = 1)
0311
0312 What: /sys/bus/usb/devices/usbX/bAlternateSetting
0313 Description:
0314 The current interface alternate setting number, in decimal.
0315
0316 See USB specs for its meaning.
0317
0318 What: /sys/bus/usb/devices/usbX/bcdDevice
0319 Description:
0320 The device's release number, in hexadecimal.
0321
0322 See USB specs for its meaning.
0323
0324 What: /sys/bus/usb/devices/usbX/bConfigurationValue
0325 Description:
0326 While a USB device typically have just one configuration
0327 setting, some devices support multiple configurations.
0328
0329 This value shows the current configuration, in decimal.
0330
0331 Changing its value will change the device's configuration
0332 to another setting.
0333
0334 The number of configurations supported by a device is at:
0335
0336 /sys/bus/usb/devices/usbX/bNumConfigurations
0337
0338 See USB specs for its meaning.
0339
0340 What: /sys/bus/usb/devices/usbX/bDeviceClass
0341 Description:
0342 Class code of the device, in hexadecimal.
0343
0344 See USB specs for its meaning.
0345
0346 What: /sys/bus/usb/devices/usbX/bDeviceProtocol
0347 Description:
0348 Protocol code of the device, in hexadecimal.
0349
0350 See USB specs for its meaning.
0351
0352 What: /sys/bus/usb/devices/usbX/bDeviceSubClass
0353 Description:
0354 Subclass code of the device, in hexadecimal.
0355
0356 See USB specs for its meaning.
0357
0358 What: /sys/bus/usb/devices/usbX/bInterfaceClass
0359 Description:
0360 Class code of the interface, in hexadecimal.
0361
0362 See USB specs for its meaning.
0363
0364 What: /sys/bus/usb/devices/usbX/bInterfaceNumber
0365 Description:
0366 Interface number, in hexadecimal.
0367
0368 See USB specs for its meaning.
0369
0370 What: /sys/bus/usb/devices/usbX/bInterfaceProtocol
0371 Description:
0372 Protocol code of the interface, in hexadecimal.
0373
0374 See USB specs for its meaning.
0375
0376 What: /sys/bus/usb/devices/usbX/bInterfaceSubClass
0377 Description:
0378 Subclass code of the interface, in hexadecimal.
0379
0380 See USB specs for its meaning.
0381
0382 What: /sys/bus/usb/devices/usbX/bmAttributes
0383 Description:
0384 Attributes of the current configuration, in hexadecimal.
0385
0386 See USB specs for its meaning.
0387
0388 What: /sys/bus/usb/devices/usbX/bMaxPacketSize0
0389 Description:
0390 Maximum endpoint 0 packet size, in decimal.
0391
0392 See USB specs for its meaning.
0393
0394 What: /sys/bus/usb/devices/usbX/bMaxPower
0395 Description:
0396 Maximum power consumption of the active configuration of
0397 the device, in miliamperes.
0398
0399 What: /sys/bus/usb/devices/usbX/bNumConfigurations
0400 Description:
0401 Number of the possible configurations of the device, in
0402 decimal. The current configuration is controlled via:
0403
0404 /sys/bus/usb/devices/usbX/bConfigurationValue
0405
0406 See USB specs for its meaning.
0407
0408 What: /sys/bus/usb/devices/usbX/bNumEndpoints
0409 Description:
0410 Number of endpoints used on this interface, in hexadecimal.
0411
0412 See USB specs for its meaning.
0413
0414 What: /sys/bus/usb/devices/usbX/bNumInterfaces
0415 Description:
0416 Number of interfaces on this device, in decimal.
0417
0418 What: /sys/bus/usb/devices/usbX/busnum
0419 Description:
0420 Number of the bus.
0421
0422 What: /sys/bus/usb/devices/usbX/configuration
0423 Description:
0424 Contents of the string descriptor associated with the
0425 current configuration. It may include the firmware version
0426 of a device and/or its serial number.
0427
0428 What: /sys/bus/usb/devices/usbX/descriptors
0429 Description:
0430 Contains the interface descriptors, in binary.
0431
0432 What: /sys/bus/usb/devices/usbX/idProduct
0433 Description:
0434 Product ID, in hexadecimal.
0435
0436 What: /sys/bus/usb/devices/usbX/idVendor
0437 Description:
0438 Vendor ID, in hexadecimal.
0439
0440 What: /sys/bus/usb/devices/usbX/devspec
0441 Description:
0442 Displays the Device Tree Open Firmware node of the interface.
0443
0444 What: /sys/bus/usb/devices/usbX/avoid_reset_quirk
0445 Description:
0446 Most devices have this set to zero.
0447
0448 If the value is 1, enable a USB quirk that prevents this
0449 device to use reset.
0450
0451 (read/write)
0452
0453 What: /sys/bus/usb/devices/usbX/devnum
0454 Description:
0455 USB interface device number, in decimal.
0456
0457 What: /sys/bus/usb/devices/usbX/devpath
0458 Description:
0459 String containing the USB interface device path.
0460
0461 What: /sys/bus/usb/devices/usbX/manufacturer
0462 Description:
0463 Vendor specific string containing the name of the
0464 manufacturer of the device.
0465
0466 What: /sys/bus/usb/devices/usbX/maxchild
0467 Description:
0468 Number of ports of an USB hub
0469
0470 What: /sys/bus/usb/devices/usbX/persist
0471 Description:
0472 Keeps the device even if it gets disconnected.
0473
0474 What: /sys/bus/usb/devices/usbX/product
0475 Description:
0476 Vendor specific string containing the name of the
0477 device's product.
0478
0479 What: /sys/bus/usb/devices/usbX/speed
0480 Description:
0481 Shows the device's max speed, according to the USB version,
0482 in Mbps.
0483 Can be:
0484
0485 ======= ====================
0486 Unknown speed unknown
0487 1.5 Low speed
0488 15 Full speed
0489 480 High Speed
0490 5000 Super Speed
0491 10000 Super Speed+
0492 20000 Super Speed+ Gen 2x2
0493 ======= ====================
0494
0495 What: /sys/bus/usb/devices/usbX/supports_autosuspend
0496 Description:
0497 Returns 1 if the device doesn't support autosuspend.
0498 Otherwise, returns 0.
0499
0500 What: /sys/bus/usb/devices/usbX/urbnum
0501 Description:
0502 Number of URBs submitted for the whole device.
0503
0504 What: /sys/bus/usb/devices/usbX/version
0505 Description:
0506 String containing the USB device version, as encoded
0507 at the BCD descriptor.
0508
0509 What: /sys/bus/usb/devices/usbX/power/autosuspend
0510 Description:
0511 Time in milliseconds for the device to autosuspend. If the
0512 value is negative, then autosuspend is prevented.
0513
0514 (read/write)
0515
0516 What: /sys/bus/usb/devices/usbX/power/active_duration
0517 Description:
0518 The total time the device has not been suspended.
0519
0520 What: /sys/bus/usb/devices/usbX/power/connected_duration
0521 Description:
0522 The total time (in msec) that the device has been connected.
0523
0524 What: /sys/bus/usb/devices/usbX/power/level
0525 Description:
0526
0527 What: /sys/bus/usb/devices/usbX/ep_<N>/bEndpointAddress
0528 Description:
0529 The address of the endpoint described by this descriptor,
0530 in hexadecimal. The endpoint direction on this bitmapped field
0531 is also shown at:
0532
0533 /sys/bus/usb/devices/usbX/ep_<N>/direction
0534
0535 See USB specs for its meaning.
0536
0537 What: /sys/bus/usb/devices/usbX/ep_<N>/bInterval
0538 Description:
0539 The interval of the endpoint as described on its descriptor,
0540 in hexadecimal. The actual interval depends on the version
0541 of the USB. Also shown in time units at
0542 /sys/bus/usb/devices/usbX/ep_<N>/interval.
0543
0544 What: /sys/bus/usb/devices/usbX/ep_<N>/bLength
0545 Description:
0546 Number of bytes of the endpoint descriptor, in hexadecimal.
0547
0548 What: /sys/bus/usb/devices/usbX/ep_<N>/bmAttributes
0549 Description:
0550 Attributes which apply to the endpoint as described on its
0551 descriptor, in hexadecimal. The endpoint type on this
0552 bitmapped field is also shown at:
0553
0554 /sys/bus/usb/devices/usbX/ep_<N>/type
0555
0556 See USB specs for its meaning.
0557
0558 What: /sys/bus/usb/devices/usbX/ep_<N>/direction
0559 Description:
0560 Direction of the endpoint. Can be:
0561
0562 - both (on control endpoints)
0563 - in
0564 - out
0565
0566 What: /sys/bus/usb/devices/usbX/ep_<N>/interval
0567 Description:
0568 Interval for polling endpoint for data transfers, in
0569 milisseconds or microseconds.
0570
0571 What: /sys/bus/usb/devices/usbX/ep_<N>/type
0572 Description:
0573 Descriptor type. Can be:
0574
0575 - Control
0576 - Isoc
0577 - Bulk
0578 - Interrupt
0579 - unknown
0580
0581 What: /sys/bus/usb/devices/usbX/ep_<N>/wMaxPacketSize
0582 Description:
0583 Maximum packet size this endpoint is capable of
0584 sending or receiving, in hexadecimal.
