| blob | bf2c1968525f01187e55d9c6a1d3638a352b9ae4 |
1 What: /sys/bus/usb/devices/INTERFACE/authorized
2 Date: August 2015
3 Description:
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
16 Date: August 2015
17 Description:
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
23 Date: July 2008
24 KernelVersion: 2.6.26
25 Contact: David Vrabel <david.vrabel@csr.com>
26 Description:
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
36 Date: July 2008
37 KernelVersion: 2.6.27
38 Contact: David Vrabel <david.vrabel@csr.com>
39 Description:
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
45 Date: July 2008
46 KernelVersion: 2.6.27
47 Contact: David Vrabel <david.vrabel@csr.com>
48 Description:
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
56 Date: July 2008
57 KernelVersion: 2.6.27
58 Contact: David Vrabel <david.vrabel@csr.com>
59 Description:
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
66 Date: October 2011
67 Contact: linux-usb@vger.kernel.org
68 Description:
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
91 line. For example::
93 # cat /sys/bus/usb/drivers/foo/new_id
94 8086 10f5
95 dead beef 06
96 f00d cafe
98 The list will be truncated at PAGE_SIZE bytes due to
99 sysfs restrictions.
101 What: /sys/bus/usb-serial/drivers/.../new_id
102 Date: October 2011
103 Contact: linux-usb@vger.kernel.org
104 Description:
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
111 Date: November 2009
112 Contact: CHENG Renquan <rqcheng@smu.edu.sg>
113 Description:
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
128 Date: September 2011
129 Contact: Andiry Xu <andiry.xu@amd.com>
130 Description:
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
143 Date: November 2015
144 Contact: Kevin Strasser <kevin.strasser@linux.intel.com>
145 Lu Baolu <baolu.lu@linux.intel.com>
146 Description:
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/.../removable
158 Date: February 2012
159 Contact: Matthew Garrett <mjg@redhat.com>
160 Description:
161 Some information about whether a given USB device is
162 physically fixed to the platform can be inferred from a
163 combination of hub descriptor bits and platform-specific data
164 such as ACPI. This file will read either "removable" or
165 "fixed" if the information is available, and "unknown"
166 otherwise.
168 What: /sys/bus/usb/devices/.../ltm_capable
169 Date: July 2012
170 Contact: Sarah Sharp <sarah.a.sharp@linux.intel.com>
171 Description:
172 USB 3.0 devices may optionally support Latency Tolerance
173 Messaging (LTM). They indicate their support by setting a bit
174 in the bmAttributes field of their SuperSpeed BOS descriptors.
175 If that bit is set for the device, ltm_capable will read "yes".
176 If the device doesn't support LTM, the file will read "no".
177 The file will be present for all speeds of USB devices, and will
178 always read "no" for USB 1.1 and USB 2.0 devices.
180 What: /sys/bus/usb/devices/.../(hub interface)/portX
181 Date: August 2012
182 Contact: Lan Tianyu <tianyu.lan@intel.com>
183 Description:
184 The /sys/bus/usb/devices/.../(hub interface)/portX
185 is usb port device's sysfs directory.
187 What: /sys/bus/usb/devices/.../(hub interface)/portX/connect_type
188 Date: January 2013
189 Contact: Lan Tianyu <tianyu.lan@intel.com>
190 Description:
191 Some platforms provide usb port connect types through ACPI.
192 This attribute is to expose these information to user space.
193 The file will read "hotplug", "hardwired" and "not used" if the
194 information is available, and "unknown" otherwise.
196 What: /sys/bus/usb/devices/.../(hub interface)/portX/location
197 Date: October 2018
198 Contact: Bjørn Mork <bjorn@mork.no>
199 Description:
200 Some platforms provide usb port physical location through
201 firmware. This is used by the kernel to pair up logical ports
202 mapping to the same physical connector. The attribute exposes the
203 raw location value as a hex integer.
206 What: /sys/bus/usb/devices/.../(hub interface)/portX/quirks
207 Date: May 2018
208 Contact: Nicolas Boichat <drinkcat@chromium.org>
209 Description:
210 In some cases, we care about time-to-active for devices
211 connected on a specific port (e.g. non-standard USB port like
212 pogo pins), where the device to be connected is known in
213 advance, and behaves well according to the specification.
214 This attribute is a bit-field that controls the behavior of
215 a specific port:
217 - Bit 0 of this field selects the "old" enumeration scheme,
218 as it is considerably faster (it only causes one USB reset
219 instead of 2).
221 The old enumeration scheme can also be selected globally
222 using /sys/module/usbcore/parameters/old_scheme_first, but
223 it is often not desirable as the new scheme was introduced to
224 increase compatibility with more devices.
225 - Bit 1 reduces TRSTRCY to the 10 ms that are required by the
226 USB 2.0 specification, instead of the 50 ms that are normally
227 used to help make enumeration work better on some high speed
228 devices.
230 What: /sys/bus/usb/devices/.../(hub interface)/portX/over_current_count
231 Date: February 2018
232 Contact: Richard Leitner <richard.leitner@skidata.com>
233 Description:
234 Most hubs are able to detect over-current situations on their
235 ports and report them to the kernel. This attribute is to expose
236 the number of over-current situation occurred on a specific port
237 to user space. This file will contain an unsigned 32 bit value
238 which wraps to 0 after its maximum is reached. This file supports
239 poll() for monitoring changes to this value in user space.
241 Any time this value changes the corresponding hub device will send a
242 udev event with the following attributes::
244 OVER_CURRENT_PORT=/sys/bus/usb/devices/.../(hub interface)/portX
245 OVER_CURRENT_COUNT=[current value of this sysfs attribute]
247 What: /sys/bus/usb/devices/.../(hub interface)/portX/usb3_lpm_permit
248 Date: November 2015
249 Contact: Lu Baolu <baolu.lu@linux.intel.com>
250 Description:
251 Some USB3.0 devices are not friendly to USB3 LPM. usb3_lpm_permit
252 attribute allows enabling/disabling usb3 lpm of a port. It takes
253 effect both before and after a usb device is enumerated. Supported
254 values are "0" if both u1 and u2 are NOT permitted, "u1" if only u1
255 is permitted, "u2" if only u2 is permitted, "u1_u2" if both u1 and
256 u2 are permitted.
258 What: /sys/bus/usb/devices/.../power/usb2_lpm_l1_timeout
259 Date: May 2013
260 Contact: Mathias Nyman <mathias.nyman@linux.intel.com>
261 Description:
262 USB 2.0 devices may support hardware link power management (LPM)
263 L1 sleep state. The usb2_lpm_l1_timeout attribute allows
264 tuning the timeout for L1 inactivity timer (LPM timer), e.g.
265 needed inactivity time before host requests the device to go to L1 sleep.
266 Useful for power management tuning.
267 Supported values are 0 - 65535 microseconds.
269 What: /sys/bus/usb/devices/.../power/usb2_lpm_besl
270 Date: May 2013
271 Contact: Mathias Nyman <mathias.nyman@linux.intel.com>
272 Description:
273 USB 2.0 devices that support hardware link power management (LPM)
274 L1 sleep state now use a best effort service latency value (BESL) to
275 indicate the best effort to resumption of service to the device after the
276 initiation of the resume event.
277 If the device does not have a preferred besl value then the host can select
278 one instead. This usb2_lpm_besl attribute allows to tune the host selected besl
279 value in order to tune power saving and service latency.
281 Supported values are 0 - 15.
282 More information on how besl values map to microseconds can be found in
283 USB 2.0 ECN Errata for Link Power Management, section 4.10)
285 What: /sys/bus/usb/devices/.../rx_lanes
286 Date: March 2018
287 Contact: Mathias Nyman <mathias.nyman@linux.intel.com>
288 Description:
289 Number of rx lanes the device is using.
290 USB 3.2 adds Dual-lane support, 2 rx and 2 tx lanes over Type-C.
291 Inter-Chip SSIC devices support asymmetric lanes up to 4 lanes per
292 direction. Devices before USB 3.2 are single lane (rx_lanes = 1)
294 What: /sys/bus/usb/devices/.../tx_lanes
295 Date: March 2018
296 Contact: Mathias Nyman <mathias.nyman@linux.intel.com>
297 Description:
298 Number of tx 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 (tx_lanes = 1)