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Based on kernel version 3.9. Page generated on 2013-05-02 22:53 EST.

1	What:		/sys/bus/usb/devices/.../power/autosuspend
2	Date:		March 2007
3	KernelVersion:	2.6.21
4	Contact:	Alan Stern <stern@rowland.harvard.edu>
5	Description:
6			Each USB device directory will contain a file named
7			power/autosuspend.  This file holds the time (in seconds)
8			the device must be idle before it will be autosuspended.
9			0 means the device will be autosuspended as soon as
10			possible.  Negative values will prevent the device from
11			being autosuspended at all, and writing a negative value
12			will resume the device if it is already suspended.
13	
14			The autosuspend delay for newly-created devices is set to
15			the value of the usbcore.autosuspend module parameter.
16	
17	What:		/sys/bus/usb/devices/.../power/persist
18	Date:		May 2007
19	KernelVersion:	2.6.23
20	Contact:	Alan Stern <stern@rowland.harvard.edu>
21	Description:
22			If CONFIG_USB_PERSIST is set, then each USB device directory
23			will contain a file named power/persist.  The file holds a
24			boolean value (0 or 1) indicating whether or not the
25			"USB-Persist" facility is enabled for the device.  Since the
26			facility is inherently dangerous, it is disabled by default
27			for all devices except hubs.  For more information, see
28			Documentation/usb/persist.txt.
29	
30	What:		/sys/bus/usb/device/.../power/connected_duration
31	Date:		January 2008
32	KernelVersion:	2.6.25
33	Contact:	Sarah Sharp <sarah.a.sharp@intel.com>
34	Description:
35			If CONFIG_PM and CONFIG_USB_SUSPEND are enabled, then this file
36			is present.  When read, it returns the total time (in msec)
37			that the USB device has been connected to the machine.  This
38			file is read-only.
39	Users:
40			PowerTOP <power@bughost.org>
41			http://www.lesswatts.org/projects/powertop/
42	
43	What:		/sys/bus/usb/device/.../power/active_duration
44	Date:		January 2008
45	KernelVersion:	2.6.25
46	Contact:	Sarah Sharp <sarah.a.sharp@intel.com>
47	Description:
48			If CONFIG_PM and CONFIG_USB_SUSPEND are enabled, then this file
49			is present.  When read, it returns the total time (in msec)
50			that the USB device has been active, i.e. not in a suspended
51			state.  This file is read-only.
52	
53			Tools can use this file and the connected_duration file to
54			compute the percentage of time that a device has been active.
55			For example,
56			echo $((100 * `cat active_duration` / `cat connected_duration`))
57			will give an integer percentage.  Note that this does not
58			account for counter wrap.
59	Users:
60			PowerTOP <power@bughost.org>
61			http://www.lesswatts.org/projects/powertop/
62	
63	What:		/sys/bus/usb/device/<busnum>-<devnum>...:<config num>-<interface num>/supports_autosuspend
64	Date:		January 2008
65	KernelVersion:	2.6.27
66	Contact:	Sarah Sharp <sarah.a.sharp@intel.com>
67	Description:
68			When read, this file returns 1 if the interface driver
69			for this interface supports autosuspend.  It also
70			returns 1 if no driver has claimed this interface, as an
71			unclaimed interface will not stop the device from being
72			autosuspended if all other interface drivers are idle.
73			The file returns 0 if autosuspend support has not been
74			added to the driver.
75	Users:
76			USB PM tool
77			git://git.moblin.org/users/sarah/usb-pm-tool/
78	
79	What:		/sys/bus/usb/device/.../authorized
80	Date:		July 2008
81	KernelVersion:	2.6.26
82	Contact:	David Vrabel <david.vrabel@csr.com>
83	Description:
84			Authorized devices are available for use by device
85			drivers, non-authorized one are not.  By default, wired
86			USB devices are authorized.
87	
88			Certified Wireless USB devices are not authorized
89			initially and should be (by writing 1) after the
90			device has been authenticated.
91	
92	What:		/sys/bus/usb/device/.../wusb_cdid
93	Date:		July 2008
94	KernelVersion:	2.6.27
95	Contact:	David Vrabel <david.vrabel@csr.com>
96	Description:
97			For Certified Wireless USB devices only.
98	
99			A devices's CDID, as 16 space-separated hex octets.
100	
101	What:		/sys/bus/usb/device/.../wusb_ck
102	Date:		July 2008
103	KernelVersion:	2.6.27
104	Contact:	David Vrabel <david.vrabel@csr.com>
105	Description:
106			For Certified Wireless USB devices only.
107	
108			Write the device's connection key (CK) to start the
109			authentication of the device.  The CK is 16
110			space-separated hex octets.
111	
112	What:		/sys/bus/usb/device/.../wusb_disconnect
113	Date:		July 2008
114	KernelVersion:	2.6.27
115	Contact:	David Vrabel <david.vrabel@csr.com>
116	Description:
117			For Certified Wireless USB devices only.
118	
119			Write a 1 to force the device to disconnect
120			(equivalent to unplugging a wired USB device).
121	
122	What:		/sys/bus/usb/drivers/.../new_id
123	Date:		October 2011
124	Contact:	linux-usb@vger.kernel.org
125	Description:
126			Writing a device ID to this file will attempt to
127			dynamically add a new device ID to a USB device driver.
128			This may allow the driver to support more hardware than
129			was included in the driver's static device ID support
130			table at compile time. The format for the device ID is:
131			idVendor idProduct bInterfaceClass.
132			The vendor ID and device ID fields are required, the
133			interface class is optional.
134			Upon successfully adding an ID, the driver will probe
135			for the device and attempt to bind to it.  For example:
136			# echo "8086 10f5" > /sys/bus/usb/drivers/foo/new_id
137	
138			Reading from this file will list all dynamically added
139			device IDs in the same format, with one entry per
140			line. For example:
141			# cat /sys/bus/usb/drivers/foo/new_id
142			8086 10f5
143			dead beef 06
144			f00d cafe
145	
146			The list will be truncated at PAGE_SIZE bytes due to
147			sysfs restrictions.
148	
149	What:		/sys/bus/usb-serial/drivers/.../new_id
150	Date:		October 2011
151	Contact:	linux-usb@vger.kernel.org
152	Description:
153			For serial USB drivers, this attribute appears under the
154			extra bus folder "usb-serial" in sysfs; apart from that
155			difference, all descriptions from the entry
156			"/sys/bus/usb/drivers/.../new_id" apply.
157	
158	What:		/sys/bus/usb/drivers/.../remove_id
159	Date:		November 2009
160	Contact:	CHENG Renquan <rqcheng@smu.edu.sg>
161	Description:
162			Writing a device ID to this file will remove an ID
163			that was dynamically added via the new_id sysfs entry.
164			The format for the device ID is:
165			idVendor idProduct.	After successfully
166			removing an ID, the driver will no longer support the
167			device.  This is useful to ensure auto probing won't
168			match the driver to the device.  For example:
169			# echo "046d c315" > /sys/bus/usb/drivers/foo/remove_id
170	
171			Reading from this file will list the dynamically added
172			device IDs, exactly like reading from the entry
173			"/sys/bus/usb/drivers/.../new_id"
174	
175	What:		/sys/bus/usb/device/.../avoid_reset_quirk
176	Date:		December 2009
177	Contact:	Oliver Neukum <oliver@neukum.org>
178	Description:
179			Writing 1 to this file tells the kernel that this
180			device will morph into another mode when it is reset.
181			Drivers will not use reset for error handling for
182			such devices.
183	Users:
184			usb_modeswitch
185	
186	What:		/sys/bus/usb/devices/.../power/usb2_hardware_lpm
187	Date:		September 2011
188	Contact:	Andiry Xu <andiry.xu@amd.com>
189	Description:
190			If CONFIG_USB_SUSPEND is set and a USB 2.0 lpm-capable device
191			is plugged in to a xHCI host which support link PM, it will
192			perform a LPM test; if the test is passed and host supports
193			USB2 hardware LPM (xHCI 1.0 feature), USB2 hardware LPM will
194			be enabled for the device and the USB device directory will
195			contain a file named power/usb2_hardware_lpm.  The file holds
196			a string value (enable or disable) indicating whether or not
197			USB2 hardware LPM is enabled for the device. Developer can
198			write y/Y/1 or n/N/0 to the file to enable/disable the
199			feature.
200	
201	What:		/sys/bus/usb/devices/.../removable
202	Date:		February 2012
203	Contact:	Matthew Garrett <mjg@redhat.com>
204	Description:
205			Some information about whether a given USB device is
206			physically fixed to the platform can be inferred from a
207			combination of hub descriptor bits and platform-specific data
208			such as ACPI. This file will read either "removable" or
209			"fixed" if the information is available, and "unknown"
210			otherwise.
211	
212	What:		/sys/bus/usb/devices/.../ltm_capable
213	Date:		July 2012
214	Contact:	Sarah Sharp <sarah.a.sharp@linux.intel.com>
215	Description:
216			USB 3.0 devices may optionally support Latency Tolerance
217			Messaging (LTM).  They indicate their support by setting a bit
218			in the bmAttributes field of their SuperSpeed BOS descriptors.
219			If that bit is set for the device, ltm_capable will read "yes".
220			If the device doesn't support LTM, the file will read "no".
221			The file will be present for all speeds of USB devices, and will
222			always read "no" for USB 1.1 and USB 2.0 devices.
223	
224	What:		/sys/bus/usb/devices/.../(hub interface)/portX
225	Date:		August 2012
226	Contact:	Lan Tianyu <tianyu.lan@intel.com>
227	Description:
228			The /sys/bus/usb/devices/.../(hub interface)/portX
229			is usb port device's sysfs directory.
230	
231	What:		/sys/bus/usb/devices/.../(hub interface)/portX/connect_type
232	Date:		January 2013
233	Contact:	Lan Tianyu <tianyu.lan@intel.com>
234	Description:
235			Some platforms provide usb port connect types through ACPI.
236			This attribute is to expose these information to user space.
237			The file will read "hotplug", "wired" and "not used" if the
238			information is available, and "unknown" otherwise.
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