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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 A deauthorized interface cannot be probed or claimed.
13
14What: /sys/bus/usb/devices/usbX/interface_authorized_default
15Date: August 2015
16Description:
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.
20
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21What: /sys/bus/usb/device/.../authorized
22Date: July 2008
23KernelVersion: 2.6.26
24Contact: David Vrabel <david.vrabel@csr.com>
25Description:
26 Authorized devices are available for use by device
27 drivers, non-authorized one are not. By default, wired
28 USB devices are authorized.
29
30 Certified Wireless USB devices are not authorized
31 initially and should be (by writing 1) after the
32 device has been authenticated.
33
34What: /sys/bus/usb/device/.../wusb_cdid
35Date: July 2008
36KernelVersion: 2.6.27
37Contact: David Vrabel <david.vrabel@csr.com>
38Description:
39 For Certified Wireless USB devices only.
40
41 A devices's CDID, as 16 space-separated hex octets.
42
43What: /sys/bus/usb/device/.../wusb_ck
44Date: July 2008
45KernelVersion: 2.6.27
46Contact: David Vrabel <david.vrabel@csr.com>
47Description:
48 For Certified Wireless USB devices only.
49
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.
53
54What: /sys/bus/usb/device/.../wusb_disconnect
55Date: July 2008
56KernelVersion: 2.6.27
57Contact: David Vrabel <david.vrabel@csr.com>
58Description:
59 For Certified Wireless USB devices only.
60
61 Write a 1 to force the device to disconnect
62 (equivalent to unplugging a wired USB device).
0c7a2b72 63
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64What: /sys/bus/usb/drivers/.../new_id
65Date: October 2011
66Contact: linux-usb@vger.kernel.org
67Description:
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:
2fc82c2d 73 idVendor idProduct bInterfaceClass RefIdVendor RefIdProduct
ff231db8 74 The vendor ID and device ID fields are required, the
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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.
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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
81
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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
85
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86 Reading from this file will list all dynamically added
87 device IDs in the same format, with one entry per
88 line. For example:
89 # cat /sys/bus/usb/drivers/foo/new_id
90 8086 10f5
91 dead beef 06
92 f00d cafe
93
94 The list will be truncated at PAGE_SIZE bytes due to
95 sysfs restrictions.
96
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97What: /sys/bus/usb-serial/drivers/.../new_id
98Date: October 2011
99Contact: linux-usb@vger.kernel.org
100Description:
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.
105
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106What: /sys/bus/usb/drivers/.../remove_id
107Date: November 2009
108Contact: CHENG Renquan <rqcheng@smu.edu.sg>
109Description:
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
ef955341 118
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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"
122
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123What: /sys/bus/usb/devices/.../power/usb2_hardware_lpm
124Date: September 2011
125Contact: Andiry Xu <andiry.xu@amd.com>
126Description:
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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.
0846e7e9 136
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137What: /sys/bus/usb/devices/.../power/usb3_hardware_lpm_u1
138 /sys/bus/usb/devices/.../power/usb3_hardware_lpm_u2
139Date: November 2015
655fe4ef 140Contact: Kevin Strasser <kevin.strasser@linux.intel.com>
bf5ce5bf 141 Lu Baolu <baolu.lu@linux.intel.com>
655fe4ef 142Description:
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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
bf5ce5bf 146 the check is passed and the host supports USB3 hardware LPM,
a2e66ad3 147 USB3 hardware LPM will be enabled for the device and the USB
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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.
655fe4ef 152
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153What: /sys/bus/usb/devices/.../removable
154Date: February 2012
155Contact: Matthew Garrett <mjg@redhat.com>
156Description:
157 Some information about whether a given USB device is
158 physically fixed to the platform can be inferred from a
c94bed8e 159 combination of hub descriptor bits and platform-specific data
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160 such as ACPI. This file will read either "removable" or
161 "fixed" if the information is available, and "unknown"
c94bed8e 162 otherwise.
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163
164What: /sys/bus/usb/devices/.../ltm_capable
165Date: July 2012
166Contact: Sarah Sharp <sarah.a.sharp@linux.intel.com>
167Description:
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.
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175
176What: /sys/bus/usb/devices/.../(hub interface)/portX
177Date: August 2012
178Contact: Lan Tianyu <tianyu.lan@intel.com>
179Description:
180 The /sys/bus/usb/devices/.../(hub interface)/portX
181 is usb port device's sysfs directory.
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182
183What: /sys/bus/usb/devices/.../(hub interface)/portX/connect_type
184Date: January 2013
185Contact: Lan Tianyu <tianyu.lan@intel.com>
186Description:
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.
17f34867 191
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192What: /sys/bus/usb/devices/.../(hub interface)/portX/usb3_lpm_permit
193Date: November 2015
194Contact: Lu Baolu <baolu.lu@linux.intel.com>
195Description:
196 Some USB3.0 devices are not friendly to USB3 LPM. usb3_lpm_permit
197 attribute allows enabling/disabling usb3 lpm of a port. It takes
198 effect both before and after a usb device is enumerated. Supported
199 values are "0" if both u1 and u2 are NOT permitted, "u1" if only u1
200 is permitted, "u2" if only u2 is permitted, "u1_u2" if both u1 and
201 u2 are permitted.
202
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203What: /sys/bus/usb/devices/.../power/usb2_lpm_l1_timeout
204Date: May 2013
205Contact: Mathias Nyman <mathias.nyman@linux.intel.com>
206Description:
207 USB 2.0 devices may support hardware link power management (LPM)
208 L1 sleep state. The usb2_lpm_l1_timeout attribute allows
209 tuning the timeout for L1 inactivity timer (LPM timer), e.g.
210 needed inactivity time before host requests the device to go to L1 sleep.
211 Useful for power management tuning.
212 Supported values are 0 - 65535 microseconds.
213
214What: /sys/bus/usb/devices/.../power/usb2_lpm_besl
215Date: May 2013
216Contact: Mathias Nyman <mathias.nyman@linux.intel.com>
217Description:
218 USB 2.0 devices that support hardware link power management (LPM)
219 L1 sleep state now use a best effort service latency value (BESL) to
220 indicate the best effort to resumption of service to the device after the
221 initiation of the resume event.
222 If the device does not have a preferred besl value then the host can select
223 one instead. This usb2_lpm_besl attribute allows to tune the host selected besl
224 value in order to tune power saving and service latency.
225
226 Supported values are 0 - 15.
227 More information on how besl values map to microseconds can be found in
228 USB 2.0 ECN Errata for Link Power Management, section 4.10)