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 31 Certified Wireless USB devices are not authorized 32 initially and should be (by writing 1) after the 33 device has been authenticated. 34 35What: /sys/bus/usb/device/.../wusb_cdid 36Date: July 2008 37KernelVersion: 2.6.27 38Contact: David Vrabel <david.vrabel@csr.com> 39Description: 40 For Certified Wireless USB devices only. 41 42 A devices's CDID, as 16 space-separated hex octets. 43 44What: /sys/bus/usb/device/.../wusb_ck 45Date: July 2008 46KernelVersion: 2.6.27 47Contact: David Vrabel <david.vrabel@csr.com> 48Description: 49 For Certified Wireless USB devices only. 50 51 Write the device's connection key (CK) to start the 52 authentication of the device. The CK is 16 53 space-separated hex octets. 54 55What: /sys/bus/usb/device/.../wusb_disconnect 56Date: July 2008 57KernelVersion: 2.6.27 58Contact: David Vrabel <david.vrabel@csr.com> 59Description: 60 For Certified Wireless USB devices only. 61 62 Write a 1 to force the device to disconnect 63 (equivalent to unplugging a wired USB device). 64 65What: /sys/bus/usb/drivers/.../new_id 66Date: October 2011 67Contact: linux-usb@vger.kernel.org 68Description: 69 Writing a device ID to this file will attempt to 70 dynamically add a new device ID to a USB device driver. 71 This may allow the driver to support more hardware than 72 was included in the driver's static device ID support 73 table at compile time. The format for the device ID is: 74 idVendor idProduct bInterfaceClass RefIdVendor RefIdProduct 75 The vendor ID and device ID fields are required, the 76 rest is optional. The `Ref*` tuple can be used to tell the 77 driver to use the same driver_data for the new device as 78 it is used for the reference device. 79 Upon successfully adding an ID, the driver will probe 80 for the device and attempt to bind to it. For example:: 81 82 # echo "8086 10f5" > /sys/bus/usb/drivers/foo/new_id 83 84 Here add a new device (0458:7045) using driver_data from 85 an already supported device (0458:704c):: 86 87 # echo "0458 7045 0 0458 704c" > /sys/bus/usb/drivers/foo/new_id 88 89 Reading from this file will list all dynamically added 90 device IDs in the same format, with one entry per 91 line. For example:: 92 93 # cat /sys/bus/usb/drivers/foo/new_id 94 8086 10f5 95 dead beef 06 96 f00d cafe 97 98 The list will be truncated at PAGE_SIZE bytes due to 99 sysfs restrictions. 100 101What: /sys/bus/usb-serial/drivers/.../new_id 102Date: October 2011 103Contact: linux-usb@vger.kernel.org 104Description: 105 For serial USB drivers, this attribute appears under the 106 extra bus folder "usb-serial" in sysfs; apart from that 107 difference, all descriptions from the entry 108 "/sys/bus/usb/drivers/.../new_id" apply. 109 110What: /sys/bus/usb/drivers/.../remove_id 111Date: November 2009 112Contact: CHENG Renquan <rqcheng@smu.edu.sg> 113Description: 114 Writing a device ID to this file will remove an ID 115 that was dynamically added via the new_id sysfs entry. 116 The format for the device ID is: 117 idVendor idProduct. After successfully 118 removing an ID, the driver will no longer support the 119 device. This is useful to ensure auto probing won't 120 match the driver to the device. For example: 121 # echo "046d c315" > /sys/bus/usb/drivers/foo/remove_id 122 123 Reading from this file will list the dynamically added 124 device IDs, exactly like reading from the entry 125 "/sys/bus/usb/drivers/.../new_id" 126 127What: /sys/bus/usb/devices/.../power/usb2_hardware_lpm 128Date: September 2011 129Contact: Andiry Xu <andiry.xu@amd.com> 130Description: 131 If CONFIG_PM is set and a USB 2.0 lpm-capable device is plugged 132 in to a xHCI host which support link PM, it will perform a LPM 133 test; if the test is passed and host supports USB2 hardware LPM 134 (xHCI 1.0 feature), USB2 hardware LPM will be enabled for the 135 device and the USB device directory will contain a file named 136 power/usb2_hardware_lpm. The file holds a string value (enable 137 or disable) indicating whether or not USB2 hardware LPM is 138 enabled for the device. Developer can write y/Y/1 or n/N/0 to 139 the file to enable/disable the feature. 140 141What: /sys/bus/usb/devices/.../power/usb3_hardware_lpm_u1 142 /sys/bus/usb/devices/.../power/usb3_hardware_lpm_u2 143Date: November 2015 144Contact: Kevin Strasser <kevin.strasser@linux.intel.com> 145 Lu Baolu <baolu.lu@linux.intel.com> 146Description: 147 If CONFIG_PM is set and a USB 3.0 lpm-capable device is plugged 148 in to a xHCI host which supports link PM, it will check if U1 149 and U2 exit latencies have been set in the BOS descriptor; if 150 the check is passed and the host supports USB3 hardware LPM, 151 USB3 hardware LPM will be enabled for the device and the USB 152 device directory will contain two files named 153 power/usb3_hardware_lpm_u1 and power/usb3_hardware_lpm_u2. These 154 files hold a string value (enable or disable) indicating whether 155 or not USB3 hardware LPM U1 or U2 is enabled for the device. 156 157What: /sys/bus/usb/devices/.../ltm_capable 158Date: July 2012 159Contact: Sarah Sharp <sarah.a.sharp@linux.intel.com> 160Description: 161 USB 3.0 devices may optionally support Latency Tolerance 162 Messaging (LTM). They indicate their support by setting a bit 163 in the bmAttributes field of their SuperSpeed BOS descriptors. 164 If that bit is set for the device, ltm_capable will read "yes". 165 If the device doesn't support LTM, the file will read "no". 166 The file will be present for all speeds of USB devices, and will 167 always read "no" for USB 1.1 and USB 2.0 devices. 168 169What: /sys/bus/usb/devices/<INTERFACE>/wireless_status 170Date: February 2023 171Contact: Bastien Nocera <hadess@hadess.net> 172Description: 173 Some USB devices use a USB receiver dongle to communicate 174 wirelessly with their device using proprietary protocols. This 175 attribute allows user-space to know whether the device is 176 connected to its receiver dongle, and, for example, consider 177 the device to be absent when choosing whether to show the 178 device's battery, show a headset in a list of outputs, or show 179 an on-screen keyboard if the only wireless keyboard is 180 turned off. 181 This attribute is not to be used to replace protocol specific 182 statuses available in WWAN, WLAN/Wi-Fi, Bluetooth, etc. 183 If the device does not use a receiver dongle with a wireless 184 device, then this attribute will not exist. 185 186What: /sys/bus/usb/devices/.../<hub_interface>/port<X> 187Date: August 2012 188Contact: Lan Tianyu <tianyu.lan@intel.com> 189Description: 190 The /sys/bus/usb/devices/.../<hub_interface>/port<X> 191 is usb port device's sysfs directory. 192 193What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/connect_type 194Date: January 2013 195Contact: Lan Tianyu <tianyu.lan@intel.com> 196Description: 197 Some platforms provide usb port connect types through ACPI. 198 This attribute is to expose these information to user space. 199 The file will read "hotplug", "hardwired" and "not used" if the 200 information is available, and "unknown" otherwise. 201 202What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/location 203Date: October 2018 204Contact: Bjørn Mork <bjorn@mork.no> 205Description: 206 Some platforms provide usb port physical location through 207 firmware. This is used by the kernel to pair up logical ports 208 mapping to the same physical connector. The attribute exposes the 209 raw location value as a hex integer. 210 211 212What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/quirks 213Date: May 2018 214Contact: Nicolas Boichat <drinkcat@chromium.org> 215Description: 216 In some cases, we care about time-to-active for devices 217 connected on a specific port (e.g. non-standard USB port like 218 pogo pins), where the device to be connected is known in 219 advance, and behaves well according to the specification. 220 This attribute is a bit-field that controls the behavior of 221 a specific port: 222 223 - Bit 0 of this field selects the "old" enumeration scheme, 224 as it is considerably faster (it only causes one USB reset 225 instead of 2). 226 227 The old enumeration scheme can also be selected globally 228 using /sys/module/usbcore/parameters/old_scheme_first, but 229 it is often not desirable as the new scheme was introduced to 230 increase compatibility with more devices. 231 - Bit 1 reduces TRSTRCY to the 10 ms that are required by the 232 USB 2.0 specification, instead of the 50 ms that are normally 233 used to help make enumeration work better on some high speed 234 devices. 235 236What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/over_current_count 237Date: February 2018 238Contact: Richard Leitner <richard.leitner@skidata.com> 239Description: 240 Most hubs are able to detect over-current situations on their 241 ports and report them to the kernel. This attribute is to expose 242 the number of over-current situation occurred on a specific port 243 to user space. This file will contain an unsigned 32 bit value 244 which wraps to 0 after its maximum is reached. This file supports 245 poll() for monitoring changes to this value in user space. 246 247 Any time this value changes the corresponding hub device will send a 248 udev event with the following attributes:: 249 250 OVER_CURRENT_PORT=/sys/bus/usb/devices/.../<hub_interface>/port<X> 251 OVER_CURRENT_COUNT=[current value of this sysfs attribute] 252 253What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/usb3_lpm_permit 254Date: November 2015 255Contact: Lu Baolu <baolu.lu@linux.intel.com> 256Description: 257 Some USB3.0 devices are not friendly to USB3 LPM. usb3_lpm_permit 258 attribute allows enabling/disabling usb3 lpm of a port. It takes 259 effect both before and after a usb device is enumerated. Supported 260 values are "0" if both u1 and u2 are NOT permitted, "u1" if only u1 261 is permitted, "u2" if only u2 is permitted, "u1_u2" if both u1 and 262 u2 are permitted. 263 264What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/connector 265Date: December 2021 266Contact: Heikki Krogerus <heikki.krogerus@linux.intel.com> 267Description: 268 Link to the USB Type-C connector when available. This link is 269 only created when USB Type-C Connector Class is enabled, and 270 only if the system firmware is capable of describing the 271 connection between a port and its connector. 272 273What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/disable 274Date: June 2022 275Contact: Michael Grzeschik <m.grzeschik@pengutronix.de> 276Description: 277 This file controls the state of a USB port, including 278 Vbus power output (but only on hubs that support 279 power switching -- most hubs don't support it). If 280 a port is disabled, the port is unusable: Devices 281 attached to the port will not be detected, initialized, 282 or enumerated. 283 284What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/early_stop 285Date: Sep 2022 286Contact: Ray Chi <raychi@google.com> 287Description: 288 Some USB hosts have some watchdog mechanisms so that the device 289 may enter ramdump if it takes a long time during port initialization. 290 This attribute allows each port just has two attempts so that the 291 port initialization will be failed quickly. In addition, if a port 292 which is marked with early_stop has failed to initialize, it will ignore 293 all future connections until this attribute is clear. 294 295What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/state 296Date: June 2023 297Contact: Roy Luo <royluo@google.com> 298Description: 299 Indicates current state of the USB device attached to the port. 300 Valid states are: 'not-attached', 'attached', 'powered', 301 'reconnecting', 'unauthenticated', 'default', 'addressed', 302 'configured', and 'suspended'. This file supports poll() to 303 monitor the state change from user space. 304 305What: /sys/bus/usb/devices/.../power/usb2_lpm_l1_timeout 306Date: May 2013 307Contact: Mathias Nyman <mathias.nyman@linux.intel.com> 308Description: 309 USB 2.0 devices may support hardware link power management (LPM) 310 L1 sleep state. The usb2_lpm_l1_timeout attribute allows 311 tuning the timeout for L1 inactivity timer (LPM timer), e.g. 312 needed inactivity time before host requests the device to go to L1 sleep. 313 Useful for power management tuning. 314 Supported values are 0 - 65535 microseconds. 315 316What: /sys/bus/usb/devices/.../power/usb2_lpm_besl 317Date: May 2013 318Contact: Mathias Nyman <mathias.nyman@linux.intel.com> 319Description: 320 USB 2.0 devices that support hardware link power management (LPM) 321 L1 sleep state now use a best effort service latency value (BESL) to 322 indicate the best effort to resumption of service to the device after the 323 initiation of the resume event. 324 If the device does not have a preferred besl value then the host can select 325 one instead. This usb2_lpm_besl attribute allows to tune the host selected besl 326 value in order to tune power saving and service latency. 327 328 Supported values are 0 - 15. 329 More information on how besl values map to microseconds can be found in 330 USB 2.0 ECN Errata for Link Power Management, section 4.10) 331 332What: /sys/bus/usb/devices/.../rx_lanes 333Date: March 2018 334Contact: Mathias Nyman <mathias.nyman@linux.intel.com> 335Description: 336 Number of rx lanes the device is using. 337 USB 3.2 adds Dual-lane support, 2 rx and 2 tx lanes over Type-C. 338 Inter-Chip SSIC devices support asymmetric lanes up to 4 lanes per 339 direction. Devices before USB 3.2 are single lane (rx_lanes = 1) 340 341What: /sys/bus/usb/devices/.../tx_lanes 342Date: March 2018 343Contact: Mathias Nyman <mathias.nyman@linux.intel.com> 344Description: 345 Number of tx lanes the device is using. 346 USB 3.2 adds Dual-lane support, 2 rx and 2 tx -lanes over Type-C. 347 Inter-Chip SSIC devices support asymmetric lanes up to 4 lanes per 348 direction. Devices before USB 3.2 are single lane (tx_lanes = 1) 349 350What: /sys/bus/usb/devices/usbX/bAlternateSetting 351Description: 352 The current interface alternate setting number, in decimal. 353 354 See USB specs for its meaning. 355 356What: /sys/bus/usb/devices/usbX/bcdDevice 357Description: 358 The device's release number, in hexadecimal. 359 360 See USB specs for its meaning. 361 362What: /sys/bus/usb/devices/usbX/bConfigurationValue 363Description: 364 While a USB device typically have just one configuration 365 setting, some devices support multiple configurations. 366 367 This value shows the current configuration, in decimal. 368 369 Changing its value will change the device's configuration 370 to another setting. 371 372 The number of configurations supported by a device is at: 373 374 /sys/bus/usb/devices/usbX/bNumConfigurations 375 376 See USB specs for its meaning. 377 378What: /sys/bus/usb/devices/usbX/bDeviceClass 379Description: 380 Class code of the device, in hexadecimal. 381 382 See USB specs for its meaning. 383 384What: /sys/bus/usb/devices/usbX/bDeviceProtocol 385Description: 386 Protocol code of the device, in hexadecimal. 387 388 See USB specs for its meaning. 389 390What: /sys/bus/usb/devices/usbX/bDeviceSubClass 391Description: 392 Subclass code of the device, in hexadecimal. 393 394 See USB specs for its meaning. 395 396What: /sys/bus/usb/devices/usbX/bInterfaceClass 397Description: 398 Class code of the interface, in hexadecimal. 399 400 See USB specs for its meaning. 401 402What: /sys/bus/usb/devices/usbX/bInterfaceNumber 403Description: 404 Interface number, in hexadecimal. 405 406 See USB specs for its meaning. 407 408What: /sys/bus/usb/devices/usbX/bInterfaceProtocol 409Description: 410 Protocol code of the interface, in hexadecimal. 411 412 See USB specs for its meaning. 413 414What: /sys/bus/usb/devices/usbX/bInterfaceSubClass 415Description: 416 Subclass code of the interface, in hexadecimal. 417 418 See USB specs for its meaning. 419 420What: /sys/bus/usb/devices/usbX/bmAttributes 421Description: 422 Attributes of the current configuration, in hexadecimal. 423 424 See USB specs for its meaning. 425 426What: /sys/bus/usb/devices/usbX/bMaxPacketSize0 427Description: 428 Maximum endpoint 0 packet size, in decimal. 429 430 See USB specs for its meaning. 431 432What: /sys/bus/usb/devices/usbX/bMaxPower 433Description: 434 Maximum power consumption of the active configuration of 435 the device, in miliamperes. 436 437What: /sys/bus/usb/devices/usbX/bNumConfigurations 438Description: 439 Number of the possible configurations of the device, in 440 decimal. The current configuration is controlled via: 441 442 /sys/bus/usb/devices/usbX/bConfigurationValue 443 444 See USB specs for its meaning. 445 446What: /sys/bus/usb/devices/usbX/bNumEndpoints 447Description: 448 Number of endpoints used on this interface, in hexadecimal. 449 450 See USB specs for its meaning. 451 452What: /sys/bus/usb/devices/usbX/bNumInterfaces 453Description: 454 Number of interfaces on this device, in decimal. 455 456What: /sys/bus/usb/devices/usbX/busnum 457Description: 458 Number of the bus. 459 460What: /sys/bus/usb/devices/usbX/configuration 461Description: 462 Contents of the string descriptor associated with the 463 current configuration. It may include the firmware version 464 of a device and/or its serial number. 465 466What: /sys/bus/usb/devices/usbX/descriptors 467Description: 468 Contains the interface descriptors, in binary. 469 470What: /sys/bus/usb/devices/usbX/idProduct 471Description: 472 Product ID, in hexadecimal. 473 474What: /sys/bus/usb/devices/usbX/idVendor 475Description: 476 Vendor ID, in hexadecimal. 477 478What: /sys/bus/usb/devices/usbX/devspec 479Description: 480 Displays the Device Tree Open Firmware node of the interface. 481 482What: /sys/bus/usb/devices/usbX/avoid_reset_quirk 483Description: 484 Most devices have this set to zero. 485 486 If the value is 1, enable a USB quirk that prevents this 487 device to use reset. 488 489 (read/write) 490 491What: /sys/bus/usb/devices/usbX/devnum 492Description: 493 USB interface device number, in decimal. 494 495What: /sys/bus/usb/devices/usbX/devpath 496Description: 497 String containing the USB interface device path. 498 499What: /sys/bus/usb/devices/usbX/manufacturer 500Description: 501 Vendor specific string containing the name of the 502 manufacturer of the device. 503 504What: /sys/bus/usb/devices/usbX/maxchild 505Description: 506 Number of ports of an USB hub 507 508What: /sys/bus/usb/devices/usbX/persist 509Description: 510 Keeps the device even if it gets disconnected. 511 512What: /sys/bus/usb/devices/usbX/product 513Description: 514 Vendor specific string containing the name of the 515 device's product. 516 517What: /sys/bus/usb/devices/usbX/speed 518Description: 519 Shows the device's max speed, according to the USB version, 520 in Mbps. 521 Can be: 522 523 ======= ==================== 524 Unknown speed unknown 525 1.5 Low speed 526 15 Full speed 527 480 High Speed 528 5000 Super Speed 529 10000 Super Speed+ 530 20000 Super Speed+ Gen 2x2 531 ======= ==================== 532 533What: /sys/bus/usb/devices/usbX/supports_autosuspend 534Description: 535 Returns 1 if the device doesn't support autosuspend. 536 Otherwise, returns 0. 537 538What: /sys/bus/usb/devices/usbX/urbnum 539Description: 540 Number of URBs submitted for the whole device. 541 542What: /sys/bus/usb/devices/usbX/version 543Description: 544 String containing the USB device version, as encoded 545 at the BCD descriptor. 546 547What: /sys/bus/usb/devices/usbX/power/autosuspend 548Description: 549 Time in milliseconds for the device to autosuspend. If the 550 value is negative, then autosuspend is prevented. 551 552 (read/write) 553 554What: /sys/bus/usb/devices/usbX/power/active_duration 555Description: 556 The total time the device has not been suspended. 557 558What: /sys/bus/usb/devices/usbX/power/connected_duration 559Description: 560 The total time (in msec) that the device has been connected. 561 562What: /sys/bus/usb/devices/usbX/power/level 563Description: 564 565What: /sys/bus/usb/devices/usbX/ep_<N>/bEndpointAddress 566Description: 567 The address of the endpoint described by this descriptor, 568 in hexadecimal. The endpoint direction on this bitmapped field 569 is also shown at: 570 571 /sys/bus/usb/devices/usbX/ep_<N>/direction 572 573 See USB specs for its meaning. 574 575What: /sys/bus/usb/devices/usbX/ep_<N>/bInterval 576Description: 577 The interval of the endpoint as described on its descriptor, 578 in hexadecimal. The actual interval depends on the version 579 of the USB. Also shown in time units at 580 /sys/bus/usb/devices/usbX/ep_<N>/interval. 581 582What: /sys/bus/usb/devices/usbX/ep_<N>/bLength 583Description: 584 Number of bytes of the endpoint descriptor, in hexadecimal. 585 586What: /sys/bus/usb/devices/usbX/ep_<N>/bmAttributes 587Description: 588 Attributes which apply to the endpoint as described on its 589 descriptor, in hexadecimal. The endpoint type on this 590 bitmapped field is also shown at: 591 592 /sys/bus/usb/devices/usbX/ep_<N>/type 593 594 See USB specs for its meaning. 595 596What: /sys/bus/usb/devices/usbX/ep_<N>/direction 597Description: 598 Direction of the endpoint. Can be: 599 600 - both (on control endpoints) 601 - in 602 - out 603 604What: /sys/bus/usb/devices/usbX/ep_<N>/interval 605Description: 606 Interval for polling endpoint for data transfers, in 607 milisseconds or microseconds. 608 609What: /sys/bus/usb/devices/usbX/ep_<N>/type 610Description: 611 Descriptor type. Can be: 612 613 - Control 614 - Isoc 615 - Bulk 616 - Interrupt 617 - unknown 618 619What: /sys/bus/usb/devices/usbX/ep_<N>/wMaxPacketSize 620Description: 621 Maximum packet size this endpoint is capable of 622 sending or receiving, in hexadecimal. 623