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/.../power/usb2_lpm_l1_timeout 296Date: May 2013 297Contact: Mathias Nyman <mathias.nyman@linux.intel.com> 298Description: 299 USB 2.0 devices may support hardware link power management (LPM) 300 L1 sleep state. The usb2_lpm_l1_timeout attribute allows 301 tuning the timeout for L1 inactivity timer (LPM timer), e.g. 302 needed inactivity time before host requests the device to go to L1 sleep. 303 Useful for power management tuning. 304 Supported values are 0 - 65535 microseconds. 305 306What: /sys/bus/usb/devices/.../power/usb2_lpm_besl 307Date: May 2013 308Contact: Mathias Nyman <mathias.nyman@linux.intel.com> 309Description: 310 USB 2.0 devices that support hardware link power management (LPM) 311 L1 sleep state now use a best effort service latency value (BESL) to 312 indicate the best effort to resumption of service to the device after the 313 initiation of the resume event. 314 If the device does not have a preferred besl value then the host can select 315 one instead. This usb2_lpm_besl attribute allows to tune the host selected besl 316 value in order to tune power saving and service latency. 317 318 Supported values are 0 - 15. 319 More information on how besl values map to microseconds can be found in 320 USB 2.0 ECN Errata for Link Power Management, section 4.10) 321 322What: /sys/bus/usb/devices/.../rx_lanes 323Date: March 2018 324Contact: Mathias Nyman <mathias.nyman@linux.intel.com> 325Description: 326 Number of rx lanes the device is using. 327 USB 3.2 adds Dual-lane support, 2 rx and 2 tx lanes over Type-C. 328 Inter-Chip SSIC devices support asymmetric lanes up to 4 lanes per 329 direction. Devices before USB 3.2 are single lane (rx_lanes = 1) 330 331What: /sys/bus/usb/devices/.../tx_lanes 332Date: March 2018 333Contact: Mathias Nyman <mathias.nyman@linux.intel.com> 334Description: 335 Number of tx lanes the device is using. 336 USB 3.2 adds Dual-lane support, 2 rx and 2 tx -lanes over Type-C. 337 Inter-Chip SSIC devices support asymmetric lanes up to 4 lanes per 338 direction. Devices before USB 3.2 are single lane (tx_lanes = 1) 339 340What: /sys/bus/usb/devices/usbX/bAlternateSetting 341Description: 342 The current interface alternate setting number, in decimal. 343 344 See USB specs for its meaning. 345 346What: /sys/bus/usb/devices/usbX/bcdDevice 347Description: 348 The device's release number, in hexadecimal. 349 350 See USB specs for its meaning. 351 352What: /sys/bus/usb/devices/usbX/bConfigurationValue 353Description: 354 While a USB device typically have just one configuration 355 setting, some devices support multiple configurations. 356 357 This value shows the current configuration, in decimal. 358 359 Changing its value will change the device's configuration 360 to another setting. 361 362 The number of configurations supported by a device is at: 363 364 /sys/bus/usb/devices/usbX/bNumConfigurations 365 366 See USB specs for its meaning. 367 368What: /sys/bus/usb/devices/usbX/bDeviceClass 369Description: 370 Class code of the device, in hexadecimal. 371 372 See USB specs for its meaning. 373 374What: /sys/bus/usb/devices/usbX/bDeviceProtocol 375Description: 376 Protocol code of the device, in hexadecimal. 377 378 See USB specs for its meaning. 379 380What: /sys/bus/usb/devices/usbX/bDeviceSubClass 381Description: 382 Subclass code of the device, in hexadecimal. 383 384 See USB specs for its meaning. 385 386What: /sys/bus/usb/devices/usbX/bInterfaceClass 387Description: 388 Class code of the interface, in hexadecimal. 389 390 See USB specs for its meaning. 391 392What: /sys/bus/usb/devices/usbX/bInterfaceNumber 393Description: 394 Interface number, in hexadecimal. 395 396 See USB specs for its meaning. 397 398What: /sys/bus/usb/devices/usbX/bInterfaceProtocol 399Description: 400 Protocol code of the interface, in hexadecimal. 401 402 See USB specs for its meaning. 403 404What: /sys/bus/usb/devices/usbX/bInterfaceSubClass 405Description: 406 Subclass code of the interface, in hexadecimal. 407 408 See USB specs for its meaning. 409 410What: /sys/bus/usb/devices/usbX/bmAttributes 411Description: 412 Attributes of the current configuration, in hexadecimal. 413 414 See USB specs for its meaning. 415 416What: /sys/bus/usb/devices/usbX/bMaxPacketSize0 417Description: 418 Maximum endpoint 0 packet size, in decimal. 419 420 See USB specs for its meaning. 421 422What: /sys/bus/usb/devices/usbX/bMaxPower 423Description: 424 Maximum power consumption of the active configuration of 425 the device, in miliamperes. 426 427What: /sys/bus/usb/devices/usbX/bNumConfigurations 428Description: 429 Number of the possible configurations of the device, in 430 decimal. The current configuration is controlled via: 431 432 /sys/bus/usb/devices/usbX/bConfigurationValue 433 434 See USB specs for its meaning. 435 436What: /sys/bus/usb/devices/usbX/bNumEndpoints 437Description: 438 Number of endpoints used on this interface, in hexadecimal. 439 440 See USB specs for its meaning. 441 442What: /sys/bus/usb/devices/usbX/bNumInterfaces 443Description: 444 Number of interfaces on this device, in decimal. 445 446What: /sys/bus/usb/devices/usbX/busnum 447Description: 448 Number of the bus. 449 450What: /sys/bus/usb/devices/usbX/configuration 451Description: 452 Contents of the string descriptor associated with the 453 current configuration. It may include the firmware version 454 of a device and/or its serial number. 455 456What: /sys/bus/usb/devices/usbX/descriptors 457Description: 458 Contains the interface descriptors, in binary. 459 460What: /sys/bus/usb/devices/usbX/idProduct 461Description: 462 Product ID, in hexadecimal. 463 464What: /sys/bus/usb/devices/usbX/idVendor 465Description: 466 Vendor ID, in hexadecimal. 467 468What: /sys/bus/usb/devices/usbX/devspec 469Description: 470 Displays the Device Tree Open Firmware node of the interface. 471 472What: /sys/bus/usb/devices/usbX/avoid_reset_quirk 473Description: 474 Most devices have this set to zero. 475 476 If the value is 1, enable a USB quirk that prevents this 477 device to use reset. 478 479 (read/write) 480 481What: /sys/bus/usb/devices/usbX/devnum 482Description: 483 USB interface device number, in decimal. 484 485What: /sys/bus/usb/devices/usbX/devpath 486Description: 487 String containing the USB interface device path. 488 489What: /sys/bus/usb/devices/usbX/manufacturer 490Description: 491 Vendor specific string containing the name of the 492 manufacturer of the device. 493 494What: /sys/bus/usb/devices/usbX/maxchild 495Description: 496 Number of ports of an USB hub 497 498What: /sys/bus/usb/devices/usbX/persist 499Description: 500 Keeps the device even if it gets disconnected. 501 502What: /sys/bus/usb/devices/usbX/product 503Description: 504 Vendor specific string containing the name of the 505 device's product. 506 507What: /sys/bus/usb/devices/usbX/speed 508Description: 509 Shows the device's max speed, according to the USB version, 510 in Mbps. 511 Can be: 512 513 ======= ==================== 514 Unknown speed unknown 515 1.5 Low speed 516 15 Full speed 517 480 High Speed 518 5000 Super Speed 519 10000 Super Speed+ 520 20000 Super Speed+ Gen 2x2 521 ======= ==================== 522 523What: /sys/bus/usb/devices/usbX/supports_autosuspend 524Description: 525 Returns 1 if the device doesn't support autosuspend. 526 Otherwise, returns 0. 527 528What: /sys/bus/usb/devices/usbX/urbnum 529Description: 530 Number of URBs submitted for the whole device. 531 532What: /sys/bus/usb/devices/usbX/version 533Description: 534 String containing the USB device version, as encoded 535 at the BCD descriptor. 536 537What: /sys/bus/usb/devices/usbX/power/autosuspend 538Description: 539 Time in milliseconds for the device to autosuspend. If the 540 value is negative, then autosuspend is prevented. 541 542 (read/write) 543 544What: /sys/bus/usb/devices/usbX/power/active_duration 545Description: 546 The total time the device has not been suspended. 547 548What: /sys/bus/usb/devices/usbX/power/connected_duration 549Description: 550 The total time (in msec) that the device has been connected. 551 552What: /sys/bus/usb/devices/usbX/power/level 553Description: 554 555What: /sys/bus/usb/devices/usbX/ep_<N>/bEndpointAddress 556Description: 557 The address of the endpoint described by this descriptor, 558 in hexadecimal. The endpoint direction on this bitmapped field 559 is also shown at: 560 561 /sys/bus/usb/devices/usbX/ep_<N>/direction 562 563 See USB specs for its meaning. 564 565What: /sys/bus/usb/devices/usbX/ep_<N>/bInterval 566Description: 567 The interval of the endpoint as described on its descriptor, 568 in hexadecimal. The actual interval depends on the version 569 of the USB. Also shown in time units at 570 /sys/bus/usb/devices/usbX/ep_<N>/interval. 571 572What: /sys/bus/usb/devices/usbX/ep_<N>/bLength 573Description: 574 Number of bytes of the endpoint descriptor, in hexadecimal. 575 576What: /sys/bus/usb/devices/usbX/ep_<N>/bmAttributes 577Description: 578 Attributes which apply to the endpoint as described on its 579 descriptor, in hexadecimal. The endpoint type on this 580 bitmapped field is also shown at: 581 582 /sys/bus/usb/devices/usbX/ep_<N>/type 583 584 See USB specs for its meaning. 585 586What: /sys/bus/usb/devices/usbX/ep_<N>/direction 587Description: 588 Direction of the endpoint. Can be: 589 590 - both (on control endpoints) 591 - in 592 - out 593 594What: /sys/bus/usb/devices/usbX/ep_<N>/interval 595Description: 596 Interval for polling endpoint for data transfers, in 597 milisseconds or microseconds. 598 599What: /sys/bus/usb/devices/usbX/ep_<N>/type 600Description: 601 Descriptor type. Can be: 602 603 - Control 604 - Isoc 605 - Bulk 606 - Interrupt 607 - unknown 608 609What: /sys/bus/usb/devices/usbX/ep_<N>/wMaxPacketSize 610Description: 611 Maximum packet size this endpoint is capable of 612 sending or receiving, in hexadecimal. 613