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_RUNTIME is set and a USB 2.0 lpm-capable device 108 is plugged in to a xHCI host which support link PM, it will 109 perform a LPM test; if the test is passed and host supports 110 USB2 hardware LPM (xHCI 1.0 feature), USB2 hardware LPM will 111 be enabled for the device and the USB device directory will 112 contain a file named power/usb2_hardware_lpm. The file holds 113 a string value (enable or disable) indicating whether or not 114 USB2 hardware LPM is enabled for the device. Developer can 115 write y/Y/1 or n/N/0 to the file to enable/disable the 116 feature. 117 118What: /sys/bus/usb/devices/.../removable 119Date: February 2012 120Contact: Matthew Garrett <mjg@redhat.com> 121Description: 122 Some information about whether a given USB device is 123 physically fixed to the platform can be inferred from a 124 combination of hub descriptor bits and platform-specific data 125 such as ACPI. This file will read either "removable" or 126 "fixed" if the information is available, and "unknown" 127 otherwise. 128 129What: /sys/bus/usb/devices/.../ltm_capable 130Date: July 2012 131Contact: Sarah Sharp <sarah.a.sharp@linux.intel.com> 132Description: 133 USB 3.0 devices may optionally support Latency Tolerance 134 Messaging (LTM). They indicate their support by setting a bit 135 in the bmAttributes field of their SuperSpeed BOS descriptors. 136 If that bit is set for the device, ltm_capable will read "yes". 137 If the device doesn't support LTM, the file will read "no". 138 The file will be present for all speeds of USB devices, and will 139 always read "no" for USB 1.1 and USB 2.0 devices. 140 141What: /sys/bus/usb/devices/.../(hub interface)/portX 142Date: August 2012 143Contact: Lan Tianyu <tianyu.lan@intel.com> 144Description: 145 The /sys/bus/usb/devices/.../(hub interface)/portX 146 is usb port device's sysfs directory. 147 148What: /sys/bus/usb/devices/.../(hub interface)/portX/connect_type 149Date: January 2013 150Contact: Lan Tianyu <tianyu.lan@intel.com> 151Description: 152 Some platforms provide usb port connect types through ACPI. 153 This attribute is to expose these information to user space. 154 The file will read "hotplug", "wired" and "not used" if the 155 information is available, and "unknown" otherwise. 156 157What: /sys/bus/usb/devices/.../power/usb2_lpm_l1_timeout 158Date: May 2013 159Contact: Mathias Nyman <mathias.nyman@linux.intel.com> 160Description: 161 USB 2.0 devices may support hardware link power management (LPM) 162 L1 sleep state. The usb2_lpm_l1_timeout attribute allows 163 tuning the timeout for L1 inactivity timer (LPM timer), e.g. 164 needed inactivity time before host requests the device to go to L1 sleep. 165 Useful for power management tuning. 166 Supported values are 0 - 65535 microseconds. 167 168What: /sys/bus/usb/devices/.../power/usb2_lpm_besl 169Date: May 2013 170Contact: Mathias Nyman <mathias.nyman@linux.intel.com> 171Description: 172 USB 2.0 devices that support hardware link power management (LPM) 173 L1 sleep state now use a best effort service latency value (BESL) to 174 indicate the best effort to resumption of service to the device after the 175 initiation of the resume event. 176 If the device does not have a preferred besl value then the host can select 177 one instead. This usb2_lpm_besl attribute allows to tune the host selected besl 178 value in order to tune power saving and service latency. 179 180 Supported values are 0 - 15. 181 More information on how besl values map to microseconds can be found in 182 USB 2.0 ECN Errata for Link Power Management, section 4.10) 183