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 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). 63 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: 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 81 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 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 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 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 118 119 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 123What: /sys/bus/usb/devices/.../power/usb2_hardware_lpm 124Date: September 2011 125Contact: Andiry Xu <andiry.xu@amd.com> 126Description: 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. 136 137What: /sys/bus/usb/devices/.../power/usb3_hardware_lpm_u1 138 /sys/bus/usb/devices/.../power/usb3_hardware_lpm_u2 139Date: November 2015 140Contact: Kevin Strasser <kevin.strasser@linux.intel.com> 141 Lu Baolu <baolu.lu@linux.intel.com> 142Description: 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. 152 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 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" 162 otherwise. 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. 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. 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", "hardwired" and "not used" if the 190 information is available, and "unknown" otherwise. 191 192What: /sys/bus/usb/devices/.../(hub interface)/portX/location 193Date: October 2018 194Contact: Bjørn Mork <bjorn@mork.no> 195Description: 196 Some platforms provide usb port physical location through 197 firmware. This is used by the kernel to pair up logical ports 198 mapping to the same physical connector. The attribute exposes the 199 raw location value as a hex integer. 200 201 202What: /sys/bus/usb/devices/.../(hub interface)/portX/quirks 203Date: May 2018 204Contact: Nicolas Boichat <drinkcat@chromium.org> 205Description: 206 In some cases, we care about time-to-active for devices 207 connected on a specific port (e.g. non-standard USB port like 208 pogo pins), where the device to be connected is known in 209 advance, and behaves well according to the specification. 210 This attribute is a bit-field that controls the behavior of 211 a specific port: 212 - Bit 0 of this field selects the "old" enumeration scheme, 213 as it is considerably faster (it only causes one USB reset 214 instead of 2). 215 The old enumeration scheme can also be selected globally 216 using /sys/module/usbcore/parameters/old_scheme_first, but 217 it is often not desirable as the new scheme was introduced to 218 increase compatibility with more devices. 219 - Bit 1 reduces TRSTRCY to the 10 ms that are required by the 220 USB 2.0 specification, instead of the 50 ms that are normally 221 used to help make enumeration work better on some high speed 222 devices. 223 224What: /sys/bus/usb/devices/.../(hub interface)/portX/over_current_count 225Date: February 2018 226Contact: Richard Leitner <richard.leitner@skidata.com> 227Description: 228 Most hubs are able to detect over-current situations on their 229 ports and report them to the kernel. This attribute is to expose 230 the number of over-current situation occurred on a specific port 231 to user space. This file will contain an unsigned 32 bit value 232 which wraps to 0 after its maximum is reached. This file supports 233 poll() for monitoring changes to this value in user space. 234 235 Any time this value changes the corresponding hub device will send a 236 udev event with the following attributes: 237 238 OVER_CURRENT_PORT=/sys/bus/usb/devices/.../(hub interface)/portX 239 OVER_CURRENT_COUNT=[current value of this sysfs attribute] 240 241What: /sys/bus/usb/devices/.../(hub interface)/portX/usb3_lpm_permit 242Date: November 2015 243Contact: Lu Baolu <baolu.lu@linux.intel.com> 244Description: 245 Some USB3.0 devices are not friendly to USB3 LPM. usb3_lpm_permit 246 attribute allows enabling/disabling usb3 lpm of a port. It takes 247 effect both before and after a usb device is enumerated. Supported 248 values are "0" if both u1 and u2 are NOT permitted, "u1" if only u1 249 is permitted, "u2" if only u2 is permitted, "u1_u2" if both u1 and 250 u2 are permitted. 251 252What: /sys/bus/usb/devices/.../power/usb2_lpm_l1_timeout 253Date: May 2013 254Contact: Mathias Nyman <mathias.nyman@linux.intel.com> 255Description: 256 USB 2.0 devices may support hardware link power management (LPM) 257 L1 sleep state. The usb2_lpm_l1_timeout attribute allows 258 tuning the timeout for L1 inactivity timer (LPM timer), e.g. 259 needed inactivity time before host requests the device to go to L1 sleep. 260 Useful for power management tuning. 261 Supported values are 0 - 65535 microseconds. 262 263What: /sys/bus/usb/devices/.../power/usb2_lpm_besl 264Date: May 2013 265Contact: Mathias Nyman <mathias.nyman@linux.intel.com> 266Description: 267 USB 2.0 devices that support hardware link power management (LPM) 268 L1 sleep state now use a best effort service latency value (BESL) to 269 indicate the best effort to resumption of service to the device after the 270 initiation of the resume event. 271 If the device does not have a preferred besl value then the host can select 272 one instead. This usb2_lpm_besl attribute allows to tune the host selected besl 273 value in order to tune power saving and service latency. 274 275 Supported values are 0 - 15. 276 More information on how besl values map to microseconds can be found in 277 USB 2.0 ECN Errata for Link Power Management, section 4.10) 278 279What: /sys/bus/usb/devices/.../rx_lanes 280Date: March 2018 281Contact: Mathias Nyman <mathias.nyman@linux.intel.com> 282Description: 283 Number of rx lanes the device is using. 284 USB 3.2 adds Dual-lane support, 2 rx and 2 tx lanes over Type-C. 285 Inter-Chip SSIC devices support asymmetric lanes up to 4 lanes per 286 direction. Devices before USB 3.2 are single lane (rx_lanes = 1) 287 288What: /sys/bus/usb/devices/.../tx_lanes 289Date: March 2018 290Contact: Mathias Nyman <mathias.nyman@linux.intel.com> 291Description: 292 Number of tx lanes the device is using. 293 USB 3.2 adds Dual-lane support, 2 rx and 2 tx -lanes over Type-C. 294 Inter-Chip SSIC devices support asymmetric lanes up to 4 lanes per 295 direction. Devices before USB 3.2 are single lane (tx_lanes = 1) 296