sysfs-bus-usb 6.6 KB

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