1What: /sys/bus/usb/device/.../authorized 2Date: July 2008 3KernelVersion: 2.6.26 4Contact: David Vrabel <david.vrabel@csr.com> 5Description: 6 Authorized devices are available for use by device 7 drivers, non-authorized one are not. By default, wired 8 USB devices are authorized. 9 10 Certified Wireless USB devices are not authorized 11 initially and should be (by writing 1) after the 12 device has been authenticated. 13 14What: /sys/bus/usb/device/.../wusb_cdid 15Date: July 2008 16KernelVersion: 2.6.27 17Contact: David Vrabel <david.vrabel@csr.com> 18Description: 19 For Certified Wireless USB devices only. 20 21 A devices's CDID, as 16 space-separated hex octets. 22 23What: /sys/bus/usb/device/.../wusb_ck 24Date: July 2008 25KernelVersion: 2.6.27 26Contact: David Vrabel <david.vrabel@csr.com> 27Description: 28 For Certified Wireless USB devices only. 29 30 Write the device's connection key (CK) to start the 31 authentication of the device. The CK is 16 32 space-separated hex octets. 33 34What: /sys/bus/usb/device/.../wusb_disconnect 35Date: July 2008 36KernelVersion: 2.6.27 37Contact: David Vrabel <david.vrabel@csr.com> 38Description: 39 For Certified Wireless USB devices only. 40 41 Write a 1 to force the device to disconnect 42 (equivalent to unplugging a wired USB device). 43 44What: /sys/bus/usb/drivers/.../new_id 45Date: October 2011 46Contact: linux-usb@vger.kernel.org 47Description: 48 Writing a device ID to this file will attempt to 49 dynamically add a new device ID to a USB device driver. 50 This may allow the driver to support more hardware than 51 was included in the driver's static device ID support 52 table at compile time. The format for the device ID is: 53 idVendor idProduct bInterfaceClass RefIdVendor RefIdProduct 54 The vendor ID and device ID fields are required, the 55 rest is optional. The Ref* tuple can be used to tell the 56 driver to use the same driver_data for the new device as 57 it is used for the reference device. 58 Upon successfully adding an ID, the driver will probe 59 for the device and attempt to bind to it. For example: 60 # echo "8086 10f5" > /sys/bus/usb/drivers/foo/new_id 61 62 Here add a new device (0458:7045) using driver_data from 63 an already supported device (0458:704c): 64 # echo "0458 7045 0 0458 704c" > /sys/bus/usb/drivers/foo/new_id 65 66 Reading from this file will list all dynamically added 67 device IDs in the same format, with one entry per 68 line. For example: 69 # cat /sys/bus/usb/drivers/foo/new_id 70 8086 10f5 71 dead beef 06 72 f00d cafe 73 74 The list will be truncated at PAGE_SIZE bytes due to 75 sysfs restrictions. 76 77What: /sys/bus/usb-serial/drivers/.../new_id 78Date: October 2011 79Contact: linux-usb@vger.kernel.org 80Description: 81 For serial USB drivers, this attribute appears under the 82 extra bus folder "usb-serial" in sysfs; apart from that 83 difference, all descriptions from the entry 84 "/sys/bus/usb/drivers/.../new_id" apply. 85 86What: /sys/bus/usb/drivers/.../remove_id 87Date: November 2009 88Contact: CHENG Renquan <rqcheng@smu.edu.sg> 89Description: 90 Writing a device ID to this file will remove an ID 91 that was dynamically added via the new_id sysfs entry. 92 The format for the device ID is: 93 idVendor idProduct. After successfully 94 removing an ID, the driver will no longer support the 95 device. This is useful to ensure auto probing won't 96 match the driver to the device. For example: 97 # echo "046d c315" > /sys/bus/usb/drivers/foo/remove_id 98 99 Reading from this file will list the dynamically added 100 device IDs, exactly like reading from the entry 101 "/sys/bus/usb/drivers/.../new_id" 102 103What: /sys/bus/usb/devices/.../power/usb2_hardware_lpm 104Date: September 2011 105Contact: Andiry Xu <andiry.xu@amd.com> 106Description: 107 If CONFIG_PM is set and a USB 2.0 lpm-capable device is plugged 108 in to a xHCI host which support link PM, it will perform a LPM 109 test; if the test is passed and host supports USB2 hardware LPM 110 (xHCI 1.0 feature), USB2 hardware LPM will be enabled for the 111 device and the USB device directory will contain a file named 112 power/usb2_hardware_lpm. The file holds a string value (enable 113 or disable) indicating whether or not USB2 hardware LPM is 114 enabled for the device. Developer can write y/Y/1 or n/N/0 to 115 the file to enable/disable the feature. 116 117What: /sys/bus/usb/devices/.../power/usb3_hardware_lpm 118Date: June 2015 119Contact: Kevin Strasser <kevin.strasser@linux.intel.com> 120Description: 121 If CONFIG_PM is set and a USB 3.0 lpm-capable device is plugged 122 in to a xHCI host which supports link PM, it will check if U1 123 and U2 exit latencies have been set in the BOS descriptor; if 124 the check is is passed and the host supports USB3 hardware LPM, 125 USB3 hardware LPM will be enabled for the device and the USB 126 device directory will contain a file named 127 power/usb3_hardware_lpm. The file holds a string value (enable 128 or disable) indicating whether or not USB3 hardware LPM is 129 enabled for the device. 130 131What: /sys/bus/usb/devices/.../removable 132Date: February 2012 133Contact: Matthew Garrett <mjg@redhat.com> 134Description: 135 Some information about whether a given USB device is 136 physically fixed to the platform can be inferred from a 137 combination of hub descriptor bits and platform-specific data 138 such as ACPI. This file will read either "removable" or 139 "fixed" if the information is available, and "unknown" 140 otherwise. 141 142What: /sys/bus/usb/devices/.../ltm_capable 143Date: July 2012 144Contact: Sarah Sharp <sarah.a.sharp@linux.intel.com> 145Description: 146 USB 3.0 devices may optionally support Latency Tolerance 147 Messaging (LTM). They indicate their support by setting a bit 148 in the bmAttributes field of their SuperSpeed BOS descriptors. 149 If that bit is set for the device, ltm_capable will read "yes". 150 If the device doesn't support LTM, the file will read "no". 151 The file will be present for all speeds of USB devices, and will 152 always read "no" for USB 1.1 and USB 2.0 devices. 153 154What: /sys/bus/usb/devices/.../(hub interface)/portX 155Date: August 2012 156Contact: Lan Tianyu <tianyu.lan@intel.com> 157Description: 158 The /sys/bus/usb/devices/.../(hub interface)/portX 159 is usb port device's sysfs directory. 160 161What: /sys/bus/usb/devices/.../(hub interface)/portX/connect_type 162Date: January 2013 163Contact: Lan Tianyu <tianyu.lan@intel.com> 164Description: 165 Some platforms provide usb port connect types through ACPI. 166 This attribute is to expose these information to user space. 167 The file will read "hotplug", "wired" and "not used" if the 168 information is available, and "unknown" otherwise. 169 170What: /sys/bus/usb/devices/.../power/usb2_lpm_l1_timeout 171Date: May 2013 172Contact: Mathias Nyman <mathias.nyman@linux.intel.com> 173Description: 174 USB 2.0 devices may support hardware link power management (LPM) 175 L1 sleep state. The usb2_lpm_l1_timeout attribute allows 176 tuning the timeout for L1 inactivity timer (LPM timer), e.g. 177 needed inactivity time before host requests the device to go to L1 sleep. 178 Useful for power management tuning. 179 Supported values are 0 - 65535 microseconds. 180 181What: /sys/bus/usb/devices/.../power/usb2_lpm_besl 182Date: May 2013 183Contact: Mathias Nyman <mathias.nyman@linux.intel.com> 184Description: 185 USB 2.0 devices that support hardware link power management (LPM) 186 L1 sleep state now use a best effort service latency value (BESL) to 187 indicate the best effort to resumption of service to the device after the 188 initiation of the resume event. 189 If the device does not have a preferred besl value then the host can select 190 one instead. This usb2_lpm_besl attribute allows to tune the host selected besl 191 value in order to tune power saving and service latency. 192 193 Supported values are 0 - 15. 194 More information on how besl values map to microseconds can be found in 195 USB 2.0 ECN Errata for Link Power Management, section 4.10) 196