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.
12 A deauthorized interface cannot be probed or claimed.
14 What: /sys/bus/usb/devices/usbX/interface_authorized_default
17 This is used as value that determines if interfaces
18 would be authorized by default.
19 The value can be 1 or 0. It's by default 1.
21 What: /sys/bus/usb/device/.../authorized
24 Contact: David Vrabel <david.vrabel@csr.com>
26 Authorized devices are available for use by device
27 drivers, non-authorized one are not. By default, wired
28 USB devices are authorized.
30 Certified Wireless USB devices are not authorized
31 initially and should be (by writing 1) after the
32 device has been authenticated.
34 What: /sys/bus/usb/device/.../wusb_cdid
37 Contact: David Vrabel <david.vrabel@csr.com>
39 For Certified Wireless USB devices only.
41 A devices's CDID, as 16 space-separated hex octets.
43 What: /sys/bus/usb/device/.../wusb_ck
46 Contact: David Vrabel <david.vrabel@csr.com>
48 For Certified Wireless USB devices only.
50 Write the device's connection key (CK) to start the
51 authentication of the device. The CK is 16
52 space-separated hex octets.
54 What: /sys/bus/usb/device/.../wusb_disconnect
57 Contact: David Vrabel <david.vrabel@csr.com>
59 For Certified Wireless USB devices only.
61 Write a 1 to force the device to disconnect
62 (equivalent to unplugging a wired USB device).
64 What: /sys/bus/usb/drivers/.../new_id
66 Contact: linux-usb@vger.kernel.org
68 Writing a device ID to this file will attempt to
69 dynamically add a new device ID to a USB device driver.
70 This may allow the driver to support more hardware than
71 was included in the driver's static device ID support
72 table at compile time. The format for the device ID is:
73 idVendor idProduct bInterfaceClass RefIdVendor RefIdProduct
74 The vendor ID and device ID fields are required, the
75 rest is optional. The Ref* tuple can be used to tell the
76 driver to use the same driver_data for the new device as
77 it is used for the reference device.
78 Upon successfully adding an ID, the driver will probe
79 for the device and attempt to bind to it. For example:
80 # echo "8086 10f5" > /sys/bus/usb/drivers/foo/new_id
82 Here add a new device (0458:7045) using driver_data from
83 an already supported device (0458:704c):
84 # echo "0458 7045 0 0458 704c" > /sys/bus/usb/drivers/foo/new_id
86 Reading from this file will list all dynamically added
87 device IDs in the same format, with one entry per
89 # cat /sys/bus/usb/drivers/foo/new_id
94 The list will be truncated at PAGE_SIZE bytes due to
97 What: /sys/bus/usb-serial/drivers/.../new_id
99 Contact: linux-usb@vger.kernel.org
101 For serial USB drivers, this attribute appears under the
102 extra bus folder "usb-serial" in sysfs; apart from that
103 difference, all descriptions from the entry
104 "/sys/bus/usb/drivers/.../new_id" apply.
106 What: /sys/bus/usb/drivers/.../remove_id
108 Contact: CHENG Renquan <rqcheng@smu.edu.sg>
110 Writing a device ID to this file will remove an ID
111 that was dynamically added via the new_id sysfs entry.
112 The format for the device ID is:
113 idVendor idProduct. After successfully
114 removing an ID, the driver will no longer support the
115 device. This is useful to ensure auto probing won't
116 match the driver to the device. For example:
117 # echo "046d c315" > /sys/bus/usb/drivers/foo/remove_id
119 Reading from this file will list the dynamically added
120 device IDs, exactly like reading from the entry
121 "/sys/bus/usb/drivers/.../new_id"
123 What: /sys/bus/usb/devices/.../power/usb2_hardware_lpm
125 Contact: Andiry Xu <andiry.xu@amd.com>
127 If CONFIG_PM is set and a USB 2.0 lpm-capable device is plugged
128 in to a xHCI host which support link PM, it will perform a LPM
129 test; if the test is passed and host supports USB2 hardware LPM
130 (xHCI 1.0 feature), USB2 hardware LPM will be enabled for the
131 device and the USB device directory will contain a file named
132 power/usb2_hardware_lpm. The file holds a string value (enable
133 or disable) indicating whether or not USB2 hardware LPM is
134 enabled for the device. Developer can write y/Y/1 or n/N/0 to
135 the file to enable/disable the feature.
137 What: /sys/bus/usb/devices/.../power/usb3_hardware_lpm_u1
138 /sys/bus/usb/devices/.../power/usb3_hardware_lpm_u2
140 Contact: Kevin Strasser <kevin.strasser@linux.intel.com>
141 Lu Baolu <baolu.lu@linux.intel.com>
143 If CONFIG_PM is set and a USB 3.0 lpm-capable device is plugged
144 in to a xHCI host which supports link PM, it will check if U1
145 and U2 exit latencies have been set in the BOS descriptor; if
146 the check is passed and the host supports USB3 hardware LPM,
147 USB3 hardware LPM will be enabled for the device and the USB
148 device directory will contain two files named
149 power/usb3_hardware_lpm_u1 and power/usb3_hardware_lpm_u2. These
150 files hold a string value (enable or disable) indicating whether
151 or not USB3 hardware LPM U1 or U2 is enabled for the device.
153 What: /sys/bus/usb/devices/.../removable
155 Contact: Matthew Garrett <mjg@redhat.com>
157 Some information about whether a given USB device is
158 physically fixed to the platform can be inferred from a
159 combination of hub descriptor bits and platform-specific data
160 such as ACPI. This file will read either "removable" or
161 "fixed" if the information is available, and "unknown"
164 What: /sys/bus/usb/devices/.../ltm_capable
166 Contact: Sarah Sharp <sarah.a.sharp@linux.intel.com>
168 USB 3.0 devices may optionally support Latency Tolerance
169 Messaging (LTM). They indicate their support by setting a bit
170 in the bmAttributes field of their SuperSpeed BOS descriptors.
171 If that bit is set for the device, ltm_capable will read "yes".
172 If the device doesn't support LTM, the file will read "no".
173 The file will be present for all speeds of USB devices, and will
174 always read "no" for USB 1.1 and USB 2.0 devices.
176 What: /sys/bus/usb/devices/.../(hub interface)/portX
178 Contact: Lan Tianyu <tianyu.lan@intel.com>
180 The /sys/bus/usb/devices/.../(hub interface)/portX
181 is usb port device's sysfs directory.
183 What: /sys/bus/usb/devices/.../(hub interface)/portX/connect_type
185 Contact: Lan Tianyu <tianyu.lan@intel.com>
187 Some platforms provide usb port connect types through ACPI.
188 This attribute is to expose these information to user space.
189 The file will read "hotplug", "wired" and "not used" if the
190 information is available, and "unknown" otherwise.
192 What: /sys/bus/usb/devices/.../(hub interface)/portX/quirks
194 Contact: Nicolas Boichat <drinkcat@chromium.org>
196 In some cases, we care about time-to-active for devices
197 connected on a specific port (e.g. non-standard USB port like
198 pogo pins), where the device to be connected is known in
199 advance, and behaves well according to the specification.
200 This attribute is a bit-field that controls the behavior of
202 - Bit 0 of this field selects the "old" enumeration scheme,
203 as it is considerably faster (it only causes one USB reset
205 The old enumeration scheme can also be selected globally
206 using /sys/module/usbcore/parameters/old_scheme_first, but
207 it is often not desirable as the new scheme was introduced to
208 increase compatibility with more devices.
209 - Bit 1 reduces TRSTRCY to the 10 ms that are required by the
210 USB 2.0 specification, instead of the 50 ms that are normally
211 used to help make enumeration work better on some high speed
214 What: /sys/bus/usb/devices/.../(hub interface)/portX/over_current_count
216 Contact: Richard Leitner <richard.leitner@skidata.com>
218 Most hubs are able to detect over-current situations on their
219 ports and report them to the kernel. This attribute is to expose
220 the number of over-current situation occurred on a specific port
221 to user space. This file will contain an unsigned 32 bit value
222 which wraps to 0 after its maximum is reached.
224 What: /sys/bus/usb/devices/.../(hub interface)/portX/usb3_lpm_permit
226 Contact: Lu Baolu <baolu.lu@linux.intel.com>
228 Some USB3.0 devices are not friendly to USB3 LPM. usb3_lpm_permit
229 attribute allows enabling/disabling usb3 lpm of a port. It takes
230 effect both before and after a usb device is enumerated. Supported
231 values are "0" if both u1 and u2 are NOT permitted, "u1" if only u1
232 is permitted, "u2" if only u2 is permitted, "u1_u2" if both u1 and
235 What: /sys/bus/usb/devices/.../power/usb2_lpm_l1_timeout
237 Contact: Mathias Nyman <mathias.nyman@linux.intel.com>
239 USB 2.0 devices may support hardware link power management (LPM)
240 L1 sleep state. The usb2_lpm_l1_timeout attribute allows
241 tuning the timeout for L1 inactivity timer (LPM timer), e.g.
242 needed inactivity time before host requests the device to go to L1 sleep.
243 Useful for power management tuning.
244 Supported values are 0 - 65535 microseconds.
246 What: /sys/bus/usb/devices/.../power/usb2_lpm_besl
248 Contact: Mathias Nyman <mathias.nyman@linux.intel.com>
250 USB 2.0 devices that support hardware link power management (LPM)
251 L1 sleep state now use a best effort service latency value (BESL) to
252 indicate the best effort to resumption of service to the device after the
253 initiation of the resume event.
254 If the device does not have a preferred besl value then the host can select
255 one instead. This usb2_lpm_besl attribute allows to tune the host selected besl
256 value in order to tune power saving and service latency.
258 Supported values are 0 - 15.
259 More information on how besl values map to microseconds can be found in
260 USB 2.0 ECN Errata for Link Power Management, section 4.10)
262 What: /sys/bus/usb/devices/.../rx_lanes
264 Contact: Mathias Nyman <mathias.nyman@linux.intel.com>
266 Number of rx lanes the device is using.
267 USB 3.2 adds Dual-lane support, 2 rx and 2 tx lanes over Type-C.
268 Inter-Chip SSIC devices support asymmetric lanes up to 4 lanes per
269 direction. Devices before USB 3.2 are single lane (rx_lanes = 1)
271 What: /sys/bus/usb/devices/.../tx_lanes
273 Contact: Mathias Nyman <mathias.nyman@linux.intel.com>
275 Number of tx lanes the device is using.
276 USB 3.2 adds Dual-lane support, 2 rx and 2 tx -lanes over Type-C.
277 Inter-Chip SSIC devices support asymmetric lanes up to 4 lanes per
278 direction. Devices before USB 3.2 are single lane (tx_lanes = 1)