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Based on kernel version 3.3. Page generated on 2012-03-23 21:23 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	What:		/sys/bus/usb-serial/drivers/.../new_id
139	Date:		October 2011
140	Contact:	linux-usb@vger.kernel.org
141	Description:
142			For serial USB drivers, this attribute appears under the
143			extra bus folder "usb-serial" in sysfs; apart from that
144			difference, all descriptions from the entry
145			"/sys/bus/usb/drivers/.../new_id" apply.
146	
147	What:		/sys/bus/usb/drivers/.../remove_id
148	Date:		November 2009
149	Contact:	CHENG Renquan <rqcheng@smu.edu.sg>
150	Description:
151			Writing a device ID to this file will remove an ID
152			that was dynamically added via the new_id sysfs entry.
153			The format for the device ID is:
154			idVendor idProduct.	After successfully
155			removing an ID, the driver will no longer support the
156			device.  This is useful to ensure auto probing won't
157			match the driver to the device.  For example:
158			# echo "046d c315" > /sys/bus/usb/drivers/foo/remove_id
159	
160	What:		/sys/bus/usb/device/.../avoid_reset_quirk
161	Date:		December 2009
162	Contact:	Oliver Neukum <oliver@neukum.org>
163	Description:
164			Writing 1 to this file tells the kernel that this
165			device will morph into another mode when it is reset.
166			Drivers will not use reset for error handling for
167			such devices.
168	Users:
169			usb_modeswitch
170	
171	What:		/sys/bus/usb/devices/.../power/usb2_hardware_lpm
172	Date:		September 2011
173	Contact:	Andiry Xu <andiry.xu@amd.com>
174	Description:
175			If CONFIG_USB_SUSPEND is set and a USB 2.0 lpm-capable device
176			is plugged in to a xHCI host which support link PM, it will
177			perform a LPM test; if the test is passed and host supports
178			USB2 hardware LPM (xHCI 1.0 feature), USB2 hardware LPM will
179			be enabled for the device and the USB device directory will
180			contain a file named power/usb2_hardware_lpm.  The file holds
181			a string value (enable or disable) indicating whether or not
182			USB2 hardware LPM is enabled for the device. Developer can
183			write y/Y/1 or n/N/0 to the file to enable/disable the
184			feature.
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