1 What: /sys/bus/usb/devices/<INTERFACE>/authorized
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.
13 A deauthorized interface cannot be probed or claimed.
15 What: /sys/bus/usb/devices/usbX/interface_authorized_default
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.
22 What: /sys/bus/usb/device/.../authorized
25 Contact: David Vrabel <david.vrabel@csr.com>
27 Authorized devices are available for use by device
28 drivers, non-authorized one are not. By default, wired
29 USB devices are authorized.
31 Certified Wireless USB devices are not authorized
32 initially and should be (by writing 1) after the
33 device has been authenticated.
35 What: /sys/bus/usb/device/.../wusb_cdid
38 Contact: David Vrabel <david.vrabel@csr.com>
40 For Certified Wireless USB devices only.
42 A devices's CDID, as 16 space-separated hex octets.
44 What: /sys/bus/usb/device/.../wusb_ck
47 Contact: David Vrabel <david.vrabel@csr.com>
49 For Certified Wireless USB devices only.
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.
55 What: /sys/bus/usb/device/.../wusb_disconnect
58 Contact: David Vrabel <david.vrabel@csr.com>
60 For Certified Wireless USB devices only.
62 Write a 1 to force the device to disconnect
63 (equivalent to unplugging a wired USB device).
65 What: /sys/bus/usb/drivers/.../new_id
67 Contact: linux-usb@vger.kernel.org
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::
82 # echo "8086 10f5" > /sys/bus/usb/drivers/foo/new_id
84 Here add a new device (0458:7045) using driver_data from
85 an already supported device (0458:704c)::
87 # echo "0458 7045 0 0458 704c" > /sys/bus/usb/drivers/foo/new_id
89 Reading from this file will list all dynamically added
90 device IDs in the same format, with one entry per
93 # cat /sys/bus/usb/drivers/foo/new_id
98 The list will be truncated at PAGE_SIZE bytes due to
101 What: /sys/bus/usb-serial/drivers/.../new_id
103 Contact: linux-usb@vger.kernel.org
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.
110 What: /sys/bus/usb/drivers/.../remove_id
112 Contact: CHENG Renquan <rqcheng@smu.edu.sg>
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
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"
127 What: /sys/bus/usb/devices/.../power/usb2_hardware_lpm
129 Contact: Andiry Xu <andiry.xu@amd.com>
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.
141 What: /sys/bus/usb/devices/.../power/usb3_hardware_lpm_u1
142 /sys/bus/usb/devices/.../power/usb3_hardware_lpm_u2
144 Contact: Kevin Strasser <kevin.strasser@linux.intel.com>
145 Lu Baolu <baolu.lu@linux.intel.com>
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.
157 What: /sys/bus/usb/devices/.../ltm_capable
159 Contact: Sarah Sharp <sarah.a.sharp@linux.intel.com>
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.
169 What: /sys/bus/usb/devices/.../<hub_interface>/port<X>
171 Contact: Lan Tianyu <tianyu.lan@intel.com>
173 The /sys/bus/usb/devices/.../<hub_interface>/port<X>
174 is usb port device's sysfs directory.
176 What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/connect_type
178 Contact: Lan Tianyu <tianyu.lan@intel.com>
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.
185 What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/location
187 Contact: Bjørn Mork <bjorn@mork.no>
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.
195 What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/quirks
197 Contact: Nicolas Boichat <drinkcat@chromium.org>
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
206 - Bit 0 of this field selects the "old" enumeration scheme,
207 as it is considerably faster (it only causes one USB reset
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
219 What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/over_current_count
221 Contact: Richard Leitner <richard.leitner@skidata.com>
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.
230 Any time this value changes the corresponding hub device will send a
231 udev event with the following attributes::
233 OVER_CURRENT_PORT=/sys/bus/usb/devices/.../<hub_interface>/port<X>
234 OVER_CURRENT_COUNT=[current value of this sysfs attribute]
236 What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/usb3_lpm_permit
238 Contact: Lu Baolu <baolu.lu@linux.intel.com>
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
247 What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/connector
249 Contact: Heikki Krogerus <heikki.krogerus@linux.intel.com>
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.
256 What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/disable
258 Contact: Michael Grzeschik <m.grzeschik@pengutronix.de>
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,
267 What: /sys/bus/usb/devices/.../power/usb2_lpm_l1_timeout
269 Contact: Mathias Nyman <mathias.nyman@linux.intel.com>
271 USB 2.0 devices may support hardware link power management (LPM)
272 L1 sleep state. The usb2_lpm_l1_timeout attribute allows
273 tuning the timeout for L1 inactivity timer (LPM timer), e.g.
274 needed inactivity time before host requests the device to go to L1 sleep.
275 Useful for power management tuning.
276 Supported values are 0 - 65535 microseconds.
278 What: /sys/bus/usb/devices/.../power/usb2_lpm_besl
280 Contact: Mathias Nyman <mathias.nyman@linux.intel.com>
282 USB 2.0 devices that support hardware link power management (LPM)
283 L1 sleep state now use a best effort service latency value (BESL) to
284 indicate the best effort to resumption of service to the device after the
285 initiation of the resume event.
286 If the device does not have a preferred besl value then the host can select
287 one instead. This usb2_lpm_besl attribute allows to tune the host selected besl
288 value in order to tune power saving and service latency.
290 Supported values are 0 - 15.
291 More information on how besl values map to microseconds can be found in
292 USB 2.0 ECN Errata for Link Power Management, section 4.10)
294 What: /sys/bus/usb/devices/.../rx_lanes
296 Contact: Mathias Nyman <mathias.nyman@linux.intel.com>
298 Number of rx lanes the device is using.
299 USB 3.2 adds Dual-lane support, 2 rx and 2 tx lanes over Type-C.
300 Inter-Chip SSIC devices support asymmetric lanes up to 4 lanes per
301 direction. Devices before USB 3.2 are single lane (rx_lanes = 1)
303 What: /sys/bus/usb/devices/.../tx_lanes
305 Contact: Mathias Nyman <mathias.nyman@linux.intel.com>
307 Number of tx lanes the device is using.
308 USB 3.2 adds Dual-lane support, 2 rx and 2 tx -lanes over Type-C.
309 Inter-Chip SSIC devices support asymmetric lanes up to 4 lanes per
310 direction. Devices before USB 3.2 are single lane (tx_lanes = 1)
312 What: /sys/bus/usb/devices/usbX/bAlternateSetting
314 The current interface alternate setting number, in decimal.
316 See USB specs for its meaning.
318 What: /sys/bus/usb/devices/usbX/bcdDevice
320 The device's release number, in hexadecimal.
322 See USB specs for its meaning.
324 What: /sys/bus/usb/devices/usbX/bConfigurationValue
326 While a USB device typically have just one configuration
327 setting, some devices support multiple configurations.
329 This value shows the current configuration, in decimal.
331 Changing its value will change the device's configuration
334 The number of configurations supported by a device is at:
336 /sys/bus/usb/devices/usbX/bNumConfigurations
338 See USB specs for its meaning.
340 What: /sys/bus/usb/devices/usbX/bDeviceClass
342 Class code of the device, in hexadecimal.
344 See USB specs for its meaning.
346 What: /sys/bus/usb/devices/usbX/bDeviceProtocol
348 Protocol code of the device, in hexadecimal.
350 See USB specs for its meaning.
352 What: /sys/bus/usb/devices/usbX/bDeviceSubClass
354 Subclass code of the device, in hexadecimal.
356 See USB specs for its meaning.
358 What: /sys/bus/usb/devices/usbX/bInterfaceClass
360 Class code of the interface, in hexadecimal.
362 See USB specs for its meaning.
364 What: /sys/bus/usb/devices/usbX/bInterfaceNumber
366 Interface number, in hexadecimal.
368 See USB specs for its meaning.
370 What: /sys/bus/usb/devices/usbX/bInterfaceProtocol
372 Protocol code of the interface, in hexadecimal.
374 See USB specs for its meaning.
376 What: /sys/bus/usb/devices/usbX/bInterfaceSubClass
378 Subclass code of the interface, in hexadecimal.
380 See USB specs for its meaning.
382 What: /sys/bus/usb/devices/usbX/bmAttributes
384 Attributes of the current configuration, in hexadecimal.
386 See USB specs for its meaning.
388 What: /sys/bus/usb/devices/usbX/bMaxPacketSize0
390 Maximum endpoint 0 packet size, in decimal.
392 See USB specs for its meaning.
394 What: /sys/bus/usb/devices/usbX/bMaxPower
396 Maximum power consumption of the active configuration of
397 the device, in miliamperes.
399 What: /sys/bus/usb/devices/usbX/bNumConfigurations
401 Number of the possible configurations of the device, in
402 decimal. The current configuration is controlled via:
404 /sys/bus/usb/devices/usbX/bConfigurationValue
406 See USB specs for its meaning.
408 What: /sys/bus/usb/devices/usbX/bNumEndpoints
410 Number of endpoints used on this interface, in hexadecimal.
412 See USB specs for its meaning.
414 What: /sys/bus/usb/devices/usbX/bNumInterfaces
416 Number of interfaces on this device, in decimal.
418 What: /sys/bus/usb/devices/usbX/busnum
422 What: /sys/bus/usb/devices/usbX/configuration
424 Contents of the string descriptor associated with the
425 current configuration. It may include the firmware version
426 of a device and/or its serial number.
428 What: /sys/bus/usb/devices/usbX/descriptors
430 Contains the interface descriptors, in binary.
432 What: /sys/bus/usb/devices/usbX/idProduct
434 Product ID, in hexadecimal.
436 What: /sys/bus/usb/devices/usbX/idVendor
438 Vendor ID, in hexadecimal.
440 What: /sys/bus/usb/devices/usbX/devspec
442 Displays the Device Tree Open Firmware node of the interface.
444 What: /sys/bus/usb/devices/usbX/avoid_reset_quirk
446 Most devices have this set to zero.
448 If the value is 1, enable a USB quirk that prevents this
453 What: /sys/bus/usb/devices/usbX/devnum
455 USB interface device number, in decimal.
457 What: /sys/bus/usb/devices/usbX/devpath
459 String containing the USB interface device path.
461 What: /sys/bus/usb/devices/usbX/manufacturer
463 Vendor specific string containing the name of the
464 manufacturer of the device.
466 What: /sys/bus/usb/devices/usbX/maxchild
468 Number of ports of an USB hub
470 What: /sys/bus/usb/devices/usbX/persist
472 Keeps the device even if it gets disconnected.
474 What: /sys/bus/usb/devices/usbX/product
476 Vendor specific string containing the name of the
479 What: /sys/bus/usb/devices/usbX/speed
481 Shows the device's max speed, according to the USB version,
485 ======= ====================
486 Unknown speed unknown
492 20000 Super Speed+ Gen 2x2
493 ======= ====================
495 What: /sys/bus/usb/devices/usbX/supports_autosuspend
497 Returns 1 if the device doesn't support autosuspend.
498 Otherwise, returns 0.
500 What: /sys/bus/usb/devices/usbX/urbnum
502 Number of URBs submitted for the whole device.
504 What: /sys/bus/usb/devices/usbX/version
506 String containing the USB device version, as encoded
507 at the BCD descriptor.
509 What: /sys/bus/usb/devices/usbX/power/autosuspend
511 Time in milliseconds for the device to autosuspend. If the
512 value is negative, then autosuspend is prevented.
516 What: /sys/bus/usb/devices/usbX/power/active_duration
518 The total time the device has not been suspended.
520 What: /sys/bus/usb/devices/usbX/power/connected_duration
522 The total time (in msec) that the device has been connected.
524 What: /sys/bus/usb/devices/usbX/power/level
527 What: /sys/bus/usb/devices/usbX/ep_<N>/bEndpointAddress
529 The address of the endpoint described by this descriptor,
530 in hexadecimal. The endpoint direction on this bitmapped field
533 /sys/bus/usb/devices/usbX/ep_<N>/direction
535 See USB specs for its meaning.
537 What: /sys/bus/usb/devices/usbX/ep_<N>/bInterval
539 The interval of the endpoint as described on its descriptor,
540 in hexadecimal. The actual interval depends on the version
541 of the USB. Also shown in time units at
542 /sys/bus/usb/devices/usbX/ep_<N>/interval.
544 What: /sys/bus/usb/devices/usbX/ep_<N>/bLength
546 Number of bytes of the endpoint descriptor, in hexadecimal.
548 What: /sys/bus/usb/devices/usbX/ep_<N>/bmAttributes
550 Attributes which apply to the endpoint as described on its
551 descriptor, in hexadecimal. The endpoint type on this
552 bitmapped field is also shown at:
554 /sys/bus/usb/devices/usbX/ep_<N>/type
556 See USB specs for its meaning.
558 What: /sys/bus/usb/devices/usbX/ep_<N>/direction
560 Direction of the endpoint. Can be:
562 - both (on control endpoints)
566 What: /sys/bus/usb/devices/usbX/ep_<N>/interval
568 Interval for polling endpoint for data transfers, in
569 milisseconds or microseconds.
571 What: /sys/bus/usb/devices/usbX/ep_<N>/type
573 Descriptor type. Can be:
581 What: /sys/bus/usb/devices/usbX/ep_<N>/wMaxPacketSize
583 Maximum packet size this endpoint is capable of
584 sending or receiving, in hexadecimal.