1What: /sys/bus/usb/devices/<INTERFACE>/authorized 2Date: August 2015 3Description: 4 This allows to authorize (1) or deauthorize (0) 5 individual interfaces instead a whole device 6 in contrast to the device authorization. 7 If a deauthorized interface will be authorized 8 so the driver probing must be triggered manually 9 by writing INTERFACE to /sys/bus/usb/drivers_probe 10 This allows to avoid side-effects with drivers 11 that need multiple interfaces. 12 13 A deauthorized interface cannot be probed or claimed. 14 15What: /sys/bus/usb/devices/usbX/interface_authorized_default 16Date: August 2015 17Description: 18 This is used as value that determines if interfaces 19 would be authorized by default. 20 The value can be 1 or 0. It's by default 1. 21 22What: /sys/bus/usb/device/.../authorized 23Date: July 2008 24KernelVersion: 2.6.26 25Contact: David Vrabel <david.vrabel@csr.com> 26Description: 27 Authorized devices are available for use by device 28 drivers, non-authorized one are not. By default, wired 29 USB devices are authorized. 30 31What: /sys/bus/usb/drivers/.../new_id 32Date: October 2011 33Contact: linux-usb@vger.kernel.org 34Description: 35 Writing a device ID to this file will attempt to 36 dynamically add a new device ID to a USB device driver. 37 This may allow the driver to support more hardware than 38 was included in the driver's static device ID support 39 table at compile time. The format for the device ID is: 40 idVendor idProduct bInterfaceClass RefIdVendor RefIdProduct 41 The vendor ID and device ID fields are required, the 42 rest is optional. The `Ref*` tuple can be used to tell the 43 driver to use the same driver_data for the new device as 44 it is used for the reference device. 45 Upon successfully adding an ID, the driver will probe 46 for the device and attempt to bind to it. For example:: 47 48 # echo "8086 10f5" > /sys/bus/usb/drivers/foo/new_id 49 50 Here add a new device (0458:7045) using driver_data from 51 an already supported device (0458:704c):: 52 53 # echo "0458 7045 0 0458 704c" > /sys/bus/usb/drivers/foo/new_id 54 55 Reading from this file will list all dynamically added 56 device IDs in the same format, with one entry per 57 line. For example:: 58 59 # cat /sys/bus/usb/drivers/foo/new_id 60 8086 10f5 61 dead beef 06 62 f00d cafe 63 64 The list will be truncated at PAGE_SIZE bytes due to 65 sysfs restrictions. 66 67What: /sys/bus/usb-serial/drivers/.../new_id 68Date: October 2011 69Contact: linux-usb@vger.kernel.org 70Description: 71 For serial USB drivers, this attribute appears under the 72 extra bus folder "usb-serial" in sysfs; apart from that 73 difference, all descriptions from the entry 74 "/sys/bus/usb/drivers/.../new_id" apply. 75 76What: /sys/bus/usb/drivers/.../remove_id 77Date: November 2009 78Contact: CHENG Renquan <rqcheng@smu.edu.sg> 79Description: 80 Writing a device ID to this file will remove an ID 81 that was dynamically added via the new_id sysfs entry. 82 The format for the device ID is: 83 idVendor idProduct. After successfully 84 removing an ID, the driver will no longer support the 85 device. This is useful to ensure auto probing won't 86 match the driver to the device. For example: 87 # echo "046d c315" > /sys/bus/usb/drivers/foo/remove_id 88 89 Reading from this file will list the dynamically added 90 device IDs, exactly like reading from the entry 91 "/sys/bus/usb/drivers/.../new_id" 92 93What: /sys/bus/usb/devices/.../power/usb2_hardware_lpm 94Date: September 2011 95Contact: Andiry Xu <andiry.xu@amd.com> 96Description: 97 If CONFIG_PM is set and a USB 2.0 lpm-capable device is plugged 98 in to a xHCI host which support link PM, it will perform a LPM 99 test; if the test is passed and host supports USB2 hardware LPM 100 (xHCI 1.0 feature), USB2 hardware LPM will be enabled for the 101 device and the USB device directory will contain a file named 102 power/usb2_hardware_lpm. The file holds a string value (enable 103 or disable) indicating whether or not USB2 hardware LPM is 104 enabled for the device. Developer can write y/Y/1 or n/N/0 to 105 the file to enable/disable the feature. 106 107What: /sys/bus/usb/devices/.../power/usb3_hardware_lpm_u1 108 /sys/bus/usb/devices/.../power/usb3_hardware_lpm_u2 109Date: November 2015 110Contact: Kevin Strasser <kevin.strasser@linux.intel.com> 111 Lu Baolu <baolu.lu@linux.intel.com> 112Description: 113 If CONFIG_PM is set and a USB 3.0 lpm-capable device is plugged 114 in to a xHCI host which supports link PM, it will check if U1 115 and U2 exit latencies have been set in the BOS descriptor; if 116 the check is passed and the host supports USB3 hardware LPM, 117 USB3 hardware LPM will be enabled for the device and the USB 118 device directory will contain two files named 119 power/usb3_hardware_lpm_u1 and power/usb3_hardware_lpm_u2. These 120 files hold a string value (enable or disable) indicating whether 121 or not USB3 hardware LPM U1 or U2 is enabled for the device. 122 123What: /sys/bus/usb/devices/.../ltm_capable 124Date: July 2012 125Contact: Sarah Sharp <sarah.a.sharp@linux.intel.com> 126Description: 127 USB 3.0 devices may optionally support Latency Tolerance 128 Messaging (LTM). They indicate their support by setting a bit 129 in the bmAttributes field of their SuperSpeed BOS descriptors. 130 If that bit is set for the device, ltm_capable will read "yes". 131 If the device doesn't support LTM, the file will read "no". 132 The file will be present for all speeds of USB devices, and will 133 always read "no" for USB 1.1 and USB 2.0 devices. 134 135What: /sys/bus/usb/devices/<INTERFACE>/wireless_status 136Date: February 2023 137Contact: Bastien Nocera <hadess@hadess.net> 138Description: 139 Some USB devices use a USB receiver dongle to communicate 140 wirelessly with their device using proprietary protocols. This 141 attribute allows user-space to know whether the device is 142 connected to its receiver dongle, and, for example, consider 143 the device to be absent when choosing whether to show the 144 device's battery, show a headset in a list of outputs, or show 145 an on-screen keyboard if the only wireless keyboard is 146 turned off. 147 This attribute is not to be used to replace protocol specific 148 statuses available in WWAN, WLAN/Wi-Fi, Bluetooth, etc. 149 If the device does not use a receiver dongle with a wireless 150 device, then this attribute will not exist. 151 152What: /sys/bus/usb/devices/.../<hub_interface>/port<X> 153Date: August 2012 154Contact: Lan Tianyu <tianyu.lan@intel.com> 155Description: 156 The /sys/bus/usb/devices/.../<hub_interface>/port<X> 157 is usb port device's sysfs directory. 158 159What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/connect_type 160Date: January 2013 161Contact: Lan Tianyu <tianyu.lan@intel.com> 162Description: 163 Some platforms provide usb port connect types through ACPI. 164 This attribute is to expose these information to user space. 165 The file will read "hotplug", "hardwired" and "not used" if the 166 information is available, and "unknown" otherwise. 167 168What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/location 169Date: October 2018 170Contact: Bj��rn Mork <bjorn@mork.no> 171Description: 172 Some platforms provide usb port physical location through 173 firmware. This is used by the kernel to pair up logical ports 174 mapping to the same physical connector. The attribute exposes the 175 raw location value as a hex integer. 176 177 178What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/quirks 179Date: May 2018 180Contact: Nicolas Boichat <drinkcat@chromium.org> 181Description: 182 In some cases, we care about time-to-active for devices 183 connected on a specific port (e.g. non-standard USB port like 184 pogo pins), where the device to be connected is known in 185 advance, and behaves well according to the specification. 186 This attribute is a bit-field that controls the behavior of 187 a specific port: 188 189 - Bit 0 of this field selects the "old" enumeration scheme, 190 as it is considerably faster (it only causes one USB reset 191 instead of 2). 192 193 The old enumeration scheme can also be selected globally 194 using /sys/module/usbcore/parameters/old_scheme_first, but 195 it is often not desirable as the new scheme was introduced to 196 increase compatibility with more devices. 197 - Bit 1 reduces TRSTRCY to the 10 ms that are required by the 198 USB 2.0 specification, instead of the 50 ms that are normally 199 used to help make enumeration work better on some high speed 200 devices. 201 202What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/over_current_count 203Date: February 2018 204Contact: Richard Leitner <richard.leitner@skidata.com> 205Description: 206 Most hubs are able to detect over-current situations on their 207 ports and report them to the kernel. This attribute is to expose 208 the number of over-current situation occurred on a specific port 209 to user space. This file will contain an unsigned 32 bit value 210 which wraps to 0 after its maximum is reached. This file supports 211 poll() for monitoring changes to this value in user space. 212 213 Any time this value changes the corresponding hub device will send a 214 udev event with the following attributes:: 215 216 OVER_CURRENT_PORT=/sys/bus/usb/devices/.../<hub_interface>/port<X> 217 OVER_CURRENT_COUNT=[current value of this sysfs attribute] 218 219What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/usb3_lpm_permit 220Date: November 2015 221Contact: Lu Baolu <baolu.lu@linux.intel.com> 222Description: 223 Some USB3.0 devices are not friendly to USB3 LPM. usb3_lpm_permit 224 attribute allows enabling/disabling usb3 lpm of a port. It takes 225 effect both before and after a usb device is enumerated. Supported 226 values are "0" if both u1 and u2 are NOT permitted, "u1" if only u1 227 is permitted, "u2" if only u2 is permitted, "u1_u2" if both u1 and 228 u2 are permitted. 229 230What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/connector 231Date: December 2021 232Contact: Heikki Krogerus <heikki.krogerus@linux.intel.com> 233Description: 234 Link to the USB Type-C connector when available. This link is 235 only created when USB Type-C Connector Class is enabled, and 236 only if the system firmware is capable of describing the 237 connection between a port and its connector. 238 239What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/disable 240Date: June 2022 241Contact: Michael Grzeschik <m.grzeschik@pengutronix.de> 242Description: 243 This file controls the state of a USB port, including 244 Vbus power output (but only on hubs that support 245 power switching -- most hubs don't support it). If 246 a port is disabled, the port is unusable: Devices 247 attached to the port will not be detected, initialized, 248 or enumerated. 249 250What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/early_stop 251Date: Sep 2022 252Contact: Ray Chi <raychi@google.com> 253Description: 254 Some USB hosts have some watchdog mechanisms so that the device 255 may enter ramdump if it takes a long time during port initialization. 256 This attribute allows each port just has two attempts so that the 257 port initialization will be failed quickly. In addition, if a port 258 which is marked with early_stop has failed to initialize, it will ignore 259 all future connections until this attribute is clear. 260 261What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/state 262Date: June 2023 263Contact: Roy Luo <royluo@google.com> 264Description: 265 Indicates current state of the USB device attached to the port. 266 Valid states are: 'not-attached', 'attached', 'powered', 267 'reconnecting', 'unauthenticated', 'default', 'addressed', 268 'configured', and 'suspended'. This file supports poll() to 269 monitor the state change from user space. 270 271What: /sys/bus/usb/devices/.../power/usb2_lpm_l1_timeout 272Date: May 2013 273Contact: Mathias Nyman <mathias.nyman@linux.intel.com> 274Description: 275 USB 2.0 devices may support hardware link power management (LPM) 276 L1 sleep state. The usb2_lpm_l1_timeout attribute allows 277 tuning the timeout for L1 inactivity timer (LPM timer), e.g. 278 needed inactivity time before host requests the device to go to L1 sleep. 279 Useful for power management tuning. 280 Supported values are 0 - 65535 microseconds. 281 282What: /sys/bus/usb/devices/.../power/usb2_lpm_besl 283Date: May 2013 284Contact: Mathias Nyman <mathias.nyman@linux.intel.com> 285Description: 286 USB 2.0 devices that support hardware link power management (LPM) 287 L1 sleep state now use a best effort service latency value (BESL) to 288 indicate the best effort to resumption of service to the device after the 289 initiation of the resume event. 290 If the device does not have a preferred besl value then the host can select 291 one instead. This usb2_lpm_besl attribute allows to tune the host selected besl 292 value in order to tune power saving and service latency. 293 294 Supported values are 0 - 15. 295 More information on how besl values map to microseconds can be found in 296 USB 2.0 ECN Errata for Link Power Management, section 4.10) 297 298What: /sys/bus/usb/devices/.../rx_lanes 299Date: March 2018 300Contact: Mathias Nyman <mathias.nyman@linux.intel.com> 301Description: 302 Number of rx lanes the device is using. 303 USB 3.2 adds Dual-lane support, 2 rx and 2 tx lanes over Type-C. 304 Inter-Chip SSIC devices support asymmetric lanes up to 4 lanes per 305 direction. Devices before USB 3.2 are single lane (rx_lanes = 1) 306 307What: /sys/bus/usb/devices/.../tx_lanes 308Date: March 2018 309Contact: Mathias Nyman <mathias.nyman@linux.intel.com> 310Description: 311 Number of tx lanes the device is using. 312 USB 3.2 adds Dual-lane support, 2 rx and 2 tx -lanes over Type-C. 313 Inter-Chip SSIC devices support asymmetric lanes up to 4 lanes per 314 direction. Devices before USB 3.2 are single lane (tx_lanes = 1) 315 316What: /sys/bus/usb/devices/.../typec 317Date: November 2023 318Contact: Heikki Krogerus <heikki.krogerus@linux.intel.com> 319Description: 320 Symlink to the USB Type-C partner device. USB Type-C partner 321 represents the component that communicates over the 322 Configuration Channel (CC signal on USB Type-C connectors and 323 cables) with the local port. 324 325What: /sys/bus/usb/devices/usbX/bAlternateSetting 326Description: 327 The current interface alternate setting number, in decimal. 328 329 See USB specs for its meaning. 330 331What: /sys/bus/usb/devices/usbX/bcdDevice 332Description: 333 The device's release number, in hexadecimal. 334 335 See USB specs for its meaning. 336 337What: /sys/bus/usb/devices/usbX/bConfigurationValue 338Description: 339 While a USB device typically have just one configuration 340 setting, some devices support multiple configurations. 341 342 This value shows the current configuration, in decimal. 343 344 Changing its value will change the device's configuration 345 to another setting. 346 347 The number of configurations supported by a device is at: 348 349 /sys/bus/usb/devices/usbX/bNumConfigurations 350 351 See USB specs for its meaning. 352 353What: /sys/bus/usb/devices/usbX/bDeviceClass 354Description: 355 Class code of the device, in hexadecimal. 356 357 See USB specs for its meaning. 358 359What: /sys/bus/usb/devices/usbX/bDeviceProtocol 360Description: 361 Protocol code of the device, in hexadecimal. 362 363 See USB specs for its meaning. 364 365What: /sys/bus/usb/devices/usbX/bDeviceSubClass 366Description: 367 Subclass code of the device, in hexadecimal. 368 369 See USB specs for its meaning. 370 371What: /sys/bus/usb/devices/usbX/bInterfaceClass 372Description: 373 Class code of the interface, in hexadecimal. 374 375 See USB specs for its meaning. 376 377What: /sys/bus/usb/devices/usbX/bInterfaceNumber 378Description: 379 Interface number, in hexadecimal. 380 381 See USB specs for its meaning. 382 383What: /sys/bus/usb/devices/usbX/bInterfaceProtocol 384Description: 385 Protocol code of the interface, in hexadecimal. 386 387 See USB specs for its meaning. 388 389What: /sys/bus/usb/devices/usbX/bInterfaceSubClass 390Description: 391 Subclass code of the interface, in hexadecimal. 392 393 See USB specs for its meaning. 394 395What: /sys/bus/usb/devices/usbX/bmAttributes 396Description: 397 Attributes of the current configuration, in hexadecimal. 398 399 See USB specs for its meaning. 400 401What: /sys/bus/usb/devices/usbX/bMaxPacketSize0 402Description: 403 Maximum endpoint 0 packet size, in decimal. 404 405 See USB specs for its meaning. 406 407What: /sys/bus/usb/devices/usbX/bMaxPower 408Description: 409 Maximum power consumption of the active configuration of 410 the device, in miliamperes. 411 412What: /sys/bus/usb/devices/usbX/bNumConfigurations 413Description: 414 Number of the possible configurations of the device, in 415 decimal. The current configuration is controlled via: 416 417 /sys/bus/usb/devices/usbX/bConfigurationValue 418 419 See USB specs for its meaning. 420 421What: /sys/bus/usb/devices/usbX/bNumEndpoints 422Description: 423 Number of endpoints used on this interface, in hexadecimal. 424 425 See USB specs for its meaning. 426 427What: /sys/bus/usb/devices/usbX/bNumInterfaces 428Description: 429 Number of interfaces on this device, in decimal. 430 431What: /sys/bus/usb/devices/usbX/busnum 432Description: 433 Number of the bus. 434 435What: /sys/bus/usb/devices/usbX/configuration 436Description: 437 Contents of the string descriptor associated with the 438 current configuration. It may include the firmware version 439 of a device and/or its serial number. 440 441What: /sys/bus/usb/devices/usbX/descriptors 442Description: 443 Contains the interface descriptors, in binary. 444 445What: /sys/bus/usb/devices/usbX/bos_descriptors 446Date: March 2024 447Contact: Elbert Mai <code@elbertmai.com> 448Description: 449 Binary file containing the cached binary device object store (BOS) 450 of the device. This consists of the BOS descriptor followed by the 451 set of device capability descriptors. All descriptors read from 452 this file are in bus-endian format. Note that the kernel will not 453 request the BOS from a device if its bcdUSB is less than 0x0201. 454 455What: /sys/bus/usb/devices/usbX/idProduct 456Description: 457 Product ID, in hexadecimal. 458 459What: /sys/bus/usb/devices/usbX/idVendor 460Description: 461 Vendor ID, in hexadecimal. 462 463What: /sys/bus/usb/devices/usbX/devspec 464Description: 465 Displays the Device Tree Open Firmware node of the interface. 466 467What: /sys/bus/usb/devices/usbX/avoid_reset_quirk 468Description: 469 Most devices have this set to zero. 470 471 If the value is 1, enable a USB quirk that prevents this 472 device to use reset. 473 474 (read/write) 475 476What: /sys/bus/usb/devices/usbX/devnum 477Description: 478 USB interface device number, in decimal. 479 480What: /sys/bus/usb/devices/usbX/devpath 481Description: 482 String containing the USB interface device path. 483 484What: /sys/bus/usb/devices/usbX/manufacturer 485Description: 486 Vendor specific string containing the name of the 487 manufacturer of the device. 488 489What: /sys/bus/usb/devices/usbX/maxchild 490Description: 491 Number of ports of an USB hub 492 493What: /sys/bus/usb/devices/usbX/persist 494Description: 495 Keeps the device even if it gets disconnected. 496 497What: /sys/bus/usb/devices/usbX/product 498Description: 499 Vendor specific string containing the name of the 500 device's product. 501 502What: /sys/bus/usb/devices/usbX/speed 503Description: 504 Shows the device's max speed, according to the USB version, 505 in Mbps. 506 Can be: 507 508 ======= ==================== 509 Unknown speed unknown 510 1.5 Low speed 511 15 Full speed 512 480 High Speed 513 5000 Super Speed 514 10000 Super Speed+ 515 20000 Super Speed+ Gen 2x2 516 ======= ==================== 517 518What: /sys/bus/usb/devices/usbX/supports_autosuspend 519Description: 520 Returns 1 if the device doesn't support autosuspend. 521 Otherwise, returns 0. 522 523What: /sys/bus/usb/devices/usbX/urbnum 524Description: 525 Number of URBs submitted for the whole device. 526 527What: /sys/bus/usb/devices/usbX/version 528Description: 529 String containing the USB device version, as encoded 530 at the BCD descriptor. 531 532What: /sys/bus/usb/devices/usbX/power/autosuspend 533Description: 534 Time in milliseconds for the device to autosuspend. If the 535 value is negative, then autosuspend is prevented. 536 537 (read/write) 538 539What: /sys/bus/usb/devices/usbX/power/active_duration 540Description: 541 The total time the device has not been suspended. 542 543What: /sys/bus/usb/devices/usbX/power/connected_duration 544Description: 545 The total time (in msec) that the device has been connected. 546 547What: /sys/bus/usb/devices/usbX/power/level 548Description: 549 550What: /sys/bus/usb/devices/usbX/ep_<N>/bEndpointAddress 551Description: 552 The address of the endpoint described by this descriptor, 553 in hexadecimal. The endpoint direction on this bitmapped field 554 is also shown at: 555 556 /sys/bus/usb/devices/usbX/ep_<N>/direction 557 558 See USB specs for its meaning. 559 560What: /sys/bus/usb/devices/usbX/ep_<N>/bInterval 561Description: 562 The interval of the endpoint as described on its descriptor, 563 in hexadecimal. The actual interval depends on the version 564 of the USB. Also shown in time units at 565 /sys/bus/usb/devices/usbX/ep_<N>/interval. 566 567What: /sys/bus/usb/devices/usbX/ep_<N>/bLength 568Description: 569 Number of bytes of the endpoint descriptor, in hexadecimal. 570 571What: /sys/bus/usb/devices/usbX/ep_<N>/bmAttributes 572Description: 573 Attributes which apply to the endpoint as described on its 574 descriptor, in hexadecimal. The endpoint type on this 575 bitmapped field is also shown at: 576 577 /sys/bus/usb/devices/usbX/ep_<N>/type 578 579 See USB specs for its meaning. 580 581What: /sys/bus/usb/devices/usbX/ep_<N>/direction 582Description: 583 Direction of the endpoint. Can be: 584 585 - both (on control endpoints) 586 - in 587 - out 588 589What: /sys/bus/usb/devices/usbX/ep_<N>/interval 590Description: 591 Interval for polling endpoint for data transfers, in 592 milisseconds or microseconds. 593 594What: /sys/bus/usb/devices/usbX/ep_<N>/type 595Description: 596 Descriptor type. Can be: 597 598 - Control 599 - Isoc 600 - Bulk 601 - Interrupt 602 - unknown 603 604What: /sys/bus/usb/devices/usbX/ep_<N>/wMaxPacketSize 605Description: 606 Maximum packet size this endpoint is capable of 607 sending or receiving, in hexadecimal. 608