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/.../<hub_interface>/port<X> 170Date: August 2012 171Contact: Lan Tianyu <tianyu.lan@intel.com> 172Description: 173 The /sys/bus/usb/devices/.../<hub_interface>/port<X> 174 is usb port device's sysfs directory. 175 176What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/connect_type 177Date: January 2013 178Contact: Lan Tianyu <tianyu.lan@intel.com> 179Description: 180 Some platforms provide usb port connect types through ACPI. 181 This attribute is to expose these information to user space. 182 The file will read "hotplug", "hardwired" and "not used" if the 183 information is available, and "unknown" otherwise. 184 185What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/location 186Date: October 2018 187Contact: Bjørn Mork <bjorn@mork.no> 188Description: 189 Some platforms provide usb port physical location through 190 firmware. This is used by the kernel to pair up logical ports 191 mapping to the same physical connector. The attribute exposes the 192 raw location value as a hex integer. 193 194 195What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/quirks 196Date: May 2018 197Contact: Nicolas Boichat <drinkcat@chromium.org> 198Description: 199 In some cases, we care about time-to-active for devices 200 connected on a specific port (e.g. non-standard USB port like 201 pogo pins), where the device to be connected is known in 202 advance, and behaves well according to the specification. 203 This attribute is a bit-field that controls the behavior of 204 a specific port: 205 206 - Bit 0 of this field selects the "old" enumeration scheme, 207 as it is considerably faster (it only causes one USB reset 208 instead of 2). 209 210 The old enumeration scheme can also be selected globally 211 using /sys/module/usbcore/parameters/old_scheme_first, but 212 it is often not desirable as the new scheme was introduced to 213 increase compatibility with more devices. 214 - Bit 1 reduces TRSTRCY to the 10 ms that are required by the 215 USB 2.0 specification, instead of the 50 ms that are normally 216 used to help make enumeration work better on some high speed 217 devices. 218 219What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/over_current_count 220Date: February 2018 221Contact: Richard Leitner <richard.leitner@skidata.com> 222Description: 223 Most hubs are able to detect over-current situations on their 224 ports and report them to the kernel. This attribute is to expose 225 the number of over-current situation occurred on a specific port 226 to user space. This file will contain an unsigned 32 bit value 227 which wraps to 0 after its maximum is reached. This file supports 228 poll() for monitoring changes to this value in user space. 229 230 Any time this value changes the corresponding hub device will send a 231 udev event with the following attributes:: 232 233 OVER_CURRENT_PORT=/sys/bus/usb/devices/.../<hub_interface>/port<X> 234 OVER_CURRENT_COUNT=[current value of this sysfs attribute] 235 236What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/usb3_lpm_permit 237Date: November 2015 238Contact: Lu Baolu <baolu.lu@linux.intel.com> 239Description: 240 Some USB3.0 devices are not friendly to USB3 LPM. usb3_lpm_permit 241 attribute allows enabling/disabling usb3 lpm of a port. It takes 242 effect both before and after a usb device is enumerated. Supported 243 values are "0" if both u1 and u2 are NOT permitted, "u1" if only u1 244 is permitted, "u2" if only u2 is permitted, "u1_u2" if both u1 and 245 u2 are permitted. 246 247What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/connector 248Date: December 2021 249Contact: Heikki Krogerus <heikki.krogerus@linux.intel.com> 250Description: 251 Link to the USB Type-C connector when available. This link is 252 only created when USB Type-C Connector Class is enabled, and 253 only if the system firmware is capable of describing the 254 connection between a port and its connector. 255 256What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/disable 257Date: June 2022 258Contact: Michael Grzeschik <m.grzeschik@pengutronix.de> 259Description: 260 This file controls the state of a USB port, including 261 Vbus power output (but only on hubs that support 262 power switching -- most hubs don't support it). If 263 a port is disabled, the port is unusable: Devices 264 attached to the port will not be detected, initialized, 265 or enumerated. 266 267What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/early_stop 268Date: Sep 2022 269Contact: Ray Chi <raychi@google.com> 270Description: 271 Some USB hosts have some watchdog mechanisms so that the device 272 may enter ramdump if it takes a long time during port initialization. 273 This attribute allows each port just has two attempts so that the 274 port initialization will be failed quickly. In addition, if a port 275 which is marked with early_stop has failed to initialize, it will ignore 276 all future connections until this attribute is clear. 277 278What: /sys/bus/usb/devices/.../power/usb2_lpm_l1_timeout 279Date: May 2013 280Contact: Mathias Nyman <mathias.nyman@linux.intel.com> 281Description: 282 USB 2.0 devices may support hardware link power management (LPM) 283 L1 sleep state. The usb2_lpm_l1_timeout attribute allows 284 tuning the timeout for L1 inactivity timer (LPM timer), e.g. 285 needed inactivity time before host requests the device to go to L1 sleep. 286 Useful for power management tuning. 287 Supported values are 0 - 65535 microseconds. 288 289What: /sys/bus/usb/devices/.../power/usb2_lpm_besl 290Date: May 2013 291Contact: Mathias Nyman <mathias.nyman@linux.intel.com> 292Description: 293 USB 2.0 devices that support hardware link power management (LPM) 294 L1 sleep state now use a best effort service latency value (BESL) to 295 indicate the best effort to resumption of service to the device after the 296 initiation of the resume event. 297 If the device does not have a preferred besl value then the host can select 298 one instead. This usb2_lpm_besl attribute allows to tune the host selected besl 299 value in order to tune power saving and service latency. 300 301 Supported values are 0 - 15. 302 More information on how besl values map to microseconds can be found in 303 USB 2.0 ECN Errata for Link Power Management, section 4.10) 304 305What: /sys/bus/usb/devices/.../rx_lanes 306Date: March 2018 307Contact: Mathias Nyman <mathias.nyman@linux.intel.com> 308Description: 309 Number of rx lanes the device is using. 310 USB 3.2 adds Dual-lane support, 2 rx and 2 tx lanes over Type-C. 311 Inter-Chip SSIC devices support asymmetric lanes up to 4 lanes per 312 direction. Devices before USB 3.2 are single lane (rx_lanes = 1) 313 314What: /sys/bus/usb/devices/.../tx_lanes 315Date: March 2018 316Contact: Mathias Nyman <mathias.nyman@linux.intel.com> 317Description: 318 Number of tx lanes the device is using. 319 USB 3.2 adds Dual-lane support, 2 rx and 2 tx -lanes over Type-C. 320 Inter-Chip SSIC devices support asymmetric lanes up to 4 lanes per 321 direction. Devices before USB 3.2 are single lane (tx_lanes = 1) 322 323What: /sys/bus/usb/devices/usbX/bAlternateSetting 324Description: 325 The current interface alternate setting number, in decimal. 326 327 See USB specs for its meaning. 328 329What: /sys/bus/usb/devices/usbX/bcdDevice 330Description: 331 The device's release number, in hexadecimal. 332 333 See USB specs for its meaning. 334 335What: /sys/bus/usb/devices/usbX/bConfigurationValue 336Description: 337 While a USB device typically have just one configuration 338 setting, some devices support multiple configurations. 339 340 This value shows the current configuration, in decimal. 341 342 Changing its value will change the device's configuration 343 to another setting. 344 345 The number of configurations supported by a device is at: 346 347 /sys/bus/usb/devices/usbX/bNumConfigurations 348 349 See USB specs for its meaning. 350 351What: /sys/bus/usb/devices/usbX/bDeviceClass 352Description: 353 Class code of the device, in hexadecimal. 354 355 See USB specs for its meaning. 356 357What: /sys/bus/usb/devices/usbX/bDeviceProtocol 358Description: 359 Protocol code of the device, in hexadecimal. 360 361 See USB specs for its meaning. 362 363What: /sys/bus/usb/devices/usbX/bDeviceSubClass 364Description: 365 Subclass code of the device, in hexadecimal. 366 367 See USB specs for its meaning. 368 369What: /sys/bus/usb/devices/usbX/bInterfaceClass 370Description: 371 Class code of the interface, in hexadecimal. 372 373 See USB specs for its meaning. 374 375What: /sys/bus/usb/devices/usbX/bInterfaceNumber 376Description: 377 Interface number, in hexadecimal. 378 379 See USB specs for its meaning. 380 381What: /sys/bus/usb/devices/usbX/bInterfaceProtocol 382Description: 383 Protocol code of the interface, in hexadecimal. 384 385 See USB specs for its meaning. 386 387What: /sys/bus/usb/devices/usbX/bInterfaceSubClass 388Description: 389 Subclass code of the interface, in hexadecimal. 390 391 See USB specs for its meaning. 392 393What: /sys/bus/usb/devices/usbX/bmAttributes 394Description: 395 Attributes of the current configuration, in hexadecimal. 396 397 See USB specs for its meaning. 398 399What: /sys/bus/usb/devices/usbX/bMaxPacketSize0 400Description: 401 Maximum endpoint 0 packet size, in decimal. 402 403 See USB specs for its meaning. 404 405What: /sys/bus/usb/devices/usbX/bMaxPower 406Description: 407 Maximum power consumption of the active configuration of 408 the device, in miliamperes. 409 410What: /sys/bus/usb/devices/usbX/bNumConfigurations 411Description: 412 Number of the possible configurations of the device, in 413 decimal. The current configuration is controlled via: 414 415 /sys/bus/usb/devices/usbX/bConfigurationValue 416 417 See USB specs for its meaning. 418 419What: /sys/bus/usb/devices/usbX/bNumEndpoints 420Description: 421 Number of endpoints used on this interface, in hexadecimal. 422 423 See USB specs for its meaning. 424 425What: /sys/bus/usb/devices/usbX/bNumInterfaces 426Description: 427 Number of interfaces on this device, in decimal. 428 429What: /sys/bus/usb/devices/usbX/busnum 430Description: 431 Number of the bus. 432 433What: /sys/bus/usb/devices/usbX/configuration 434Description: 435 Contents of the string descriptor associated with the 436 current configuration. It may include the firmware version 437 of a device and/or its serial number. 438 439What: /sys/bus/usb/devices/usbX/descriptors 440Description: 441 Contains the interface descriptors, in binary. 442 443What: /sys/bus/usb/devices/usbX/idProduct 444Description: 445 Product ID, in hexadecimal. 446 447What: /sys/bus/usb/devices/usbX/idVendor 448Description: 449 Vendor ID, in hexadecimal. 450 451What: /sys/bus/usb/devices/usbX/devspec 452Description: 453 Displays the Device Tree Open Firmware node of the interface. 454 455What: /sys/bus/usb/devices/usbX/avoid_reset_quirk 456Description: 457 Most devices have this set to zero. 458 459 If the value is 1, enable a USB quirk that prevents this 460 device to use reset. 461 462 (read/write) 463 464What: /sys/bus/usb/devices/usbX/devnum 465Description: 466 USB interface device number, in decimal. 467 468What: /sys/bus/usb/devices/usbX/devpath 469Description: 470 String containing the USB interface device path. 471 472What: /sys/bus/usb/devices/usbX/manufacturer 473Description: 474 Vendor specific string containing the name of the 475 manufacturer of the device. 476 477What: /sys/bus/usb/devices/usbX/maxchild 478Description: 479 Number of ports of an USB hub 480 481What: /sys/bus/usb/devices/usbX/persist 482Description: 483 Keeps the device even if it gets disconnected. 484 485What: /sys/bus/usb/devices/usbX/product 486Description: 487 Vendor specific string containing the name of the 488 device's product. 489 490What: /sys/bus/usb/devices/usbX/speed 491Description: 492 Shows the device's max speed, according to the USB version, 493 in Mbps. 494 Can be: 495 496 ======= ==================== 497 Unknown speed unknown 498 1.5 Low speed 499 15 Full speed 500 480 High Speed 501 5000 Super Speed 502 10000 Super Speed+ 503 20000 Super Speed+ Gen 2x2 504 ======= ==================== 505 506What: /sys/bus/usb/devices/usbX/supports_autosuspend 507Description: 508 Returns 1 if the device doesn't support autosuspend. 509 Otherwise, returns 0. 510 511What: /sys/bus/usb/devices/usbX/urbnum 512Description: 513 Number of URBs submitted for the whole device. 514 515What: /sys/bus/usb/devices/usbX/version 516Description: 517 String containing the USB device version, as encoded 518 at the BCD descriptor. 519 520What: /sys/bus/usb/devices/usbX/power/autosuspend 521Description: 522 Time in milliseconds for the device to autosuspend. If the 523 value is negative, then autosuspend is prevented. 524 525 (read/write) 526 527What: /sys/bus/usb/devices/usbX/power/active_duration 528Description: 529 The total time the device has not been suspended. 530 531What: /sys/bus/usb/devices/usbX/power/connected_duration 532Description: 533 The total time (in msec) that the device has been connected. 534 535What: /sys/bus/usb/devices/usbX/power/level 536Description: 537 538What: /sys/bus/usb/devices/usbX/ep_<N>/bEndpointAddress 539Description: 540 The address of the endpoint described by this descriptor, 541 in hexadecimal. The endpoint direction on this bitmapped field 542 is also shown at: 543 544 /sys/bus/usb/devices/usbX/ep_<N>/direction 545 546 See USB specs for its meaning. 547 548What: /sys/bus/usb/devices/usbX/ep_<N>/bInterval 549Description: 550 The interval of the endpoint as described on its descriptor, 551 in hexadecimal. The actual interval depends on the version 552 of the USB. Also shown in time units at 553 /sys/bus/usb/devices/usbX/ep_<N>/interval. 554 555What: /sys/bus/usb/devices/usbX/ep_<N>/bLength 556Description: 557 Number of bytes of the endpoint descriptor, in hexadecimal. 558 559What: /sys/bus/usb/devices/usbX/ep_<N>/bmAttributes 560Description: 561 Attributes which apply to the endpoint as described on its 562 descriptor, in hexadecimal. The endpoint type on this 563 bitmapped field is also shown at: 564 565 /sys/bus/usb/devices/usbX/ep_<N>/type 566 567 See USB specs for its meaning. 568 569What: /sys/bus/usb/devices/usbX/ep_<N>/direction 570Description: 571 Direction of the endpoint. Can be: 572 573 - both (on control endpoints) 574 - in 575 - out 576 577What: /sys/bus/usb/devices/usbX/ep_<N>/interval 578Description: 579 Interval for polling endpoint for data transfers, in 580 milisseconds or microseconds. 581 582What: /sys/bus/usb/devices/usbX/ep_<N>/type 583Description: 584 Descriptor type. Can be: 585 586 - Control 587 - Isoc 588 - Bulk 589 - Interrupt 590 - unknown 591 592What: /sys/bus/usb/devices/usbX/ep_<N>/wMaxPacketSize 593Description: 594 Maximum packet size this endpoint is capable of 595 sending or receiving, in hexadecimal. 596