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+What:           /sys/bus/usb/devices/.../power/persist
+Date:           May 2007
+KernelVersion:  2.6.23
+Contact:        Alan Stern <stern@rowland.harvard.edu>
+Description:
+                If CONFIG_USB_PERSIST is set, then each USB device directory
+                will contain a file named power/persist.  The file holds a
+                boolean value (0 or 1) indicating whether or not the
+                "USB-Persist" facility is enabled for the device.  Since the
+                facility is inherently dangerous, it is disabled by default
+                for all devices except hubs.  For more information, see
+                Documentation/usb/persist.txt.
+
+What:           /sys/bus/usb/devices/.../power/autosuspend
+Date:           March 2007
+KernelVersion:  2.6.21
+Contact:        Alan Stern <stern@rowland.harvard.edu>
+Description:
+                Each USB device directory will contain a file named
+                power/autosuspend.  This file holds the time (in seconds)
+                the device must be idle before it will be autosuspended.
+                0 means the device will be autosuspended as soon as
+                possible.  Negative values will prevent the device from
+                being autosuspended at all, and writing a negative value
+                will resume the device if it is already suspended.
+
+                The autosuspend delay for newly-created devices is set to
+                the value of the usbcore.autosuspend module parameter.
+
+What:           /sys/bus/usb/device/.../power/connected_duration
+Date:           January 2008
+KernelVersion:  2.6.25
+Contact:        Sarah Sharp <sarah.a.sharp@intel.com>
+Description:
+                If CONFIG_PM_RUNTIME is enabled then this file
+                is present.  When read, it returns the total time (in msec)
+                that the USB device has been connected to the machine.  This
+                file is read-only.
+Users:
+                PowerTOP <powertop@lists.01.org>
+                https://01.org/powertop/
+
+What:           /sys/bus/usb/device/.../power/active_duration
+Date:           January 2008
+KernelVersion:  2.6.25
+Contact:        Sarah Sharp <sarah.a.sharp@intel.com>
+Description:
+                If CONFIG_PM_RUNTIME is enabled then this file
+                is present.  When read, it returns the total time (in msec)
+                that the USB device has been active, i.e. not in a suspended
+                state.  This file is read-only.
+
+                Tools can use this file and the connected_duration file to
+                compute the percentage of time that a device has been active.
+                For example,
+                echo $((100 * `cat active_duration` / `cat connected_duration`))
+                will give an integer percentage.  Note that this does not
+                account for counter wrap.
+Users:
+                PowerTOP <powertop@lists.01.org>
+                https://01.org/powertop/
+
+What:           /sys/bus/usb/devices/<busnum>-<port[.port]>...:<config num>-<interface num>/supports_autosuspend
+Date:           January 2008
+KernelVersion:  2.6.27
+Contact:        Sarah Sharp <sarah.a.sharp@intel.com>
+Description:
+                When read, this file returns 1 if the interface driver
+                for this interface supports autosuspend.  It also
+                returns 1 if no driver has claimed this interface, as an
+                unclaimed interface will not stop the device from being
+                autosuspended if all other interface drivers are idle.
+                The file returns 0 if autosuspend support has not been
+                added to the driver.
+Users:
+                USB PM tool
+                git://git.moblin.org/users/sarah/usb-pm-tool/
+
+What:           /sys/bus/usb/device/.../avoid_reset_quirk
+Date:           December 2009
+Contact:        Oliver Neukum <oliver@neukum.org>
+Description:
+                Writing 1 to this file tells the kernel that this
+                device will morph into another mode when it is reset.
+                Drivers will not use reset for error handling for
+                such devices.
+Users:
+                usb_modeswitch
+
+What:           /sys/bus/usb/devices/.../devnum
+KernelVersion:  since at least 2.6.18
+Description:
+                Device address on the USB bus.
+Users:
+                libusb
+
+What:           /sys/bus/usb/devices/.../bConfigurationValue
+KernelVersion:  since at least 2.6.18
+Description:
+                bConfigurationValue of the *active* configuration for the
+                device. Writing 0 or -1 to bConfigurationValue will reset the
+                active configuration (unconfigure the device). Writing
+                another value will change the active configuration.
+
+                Note that some devices, in violation of the USB spec, have a
+                configuration with a value equal to 0. Writing 0 to
+                bConfigurationValue for these devices will install that
+                configuration, rather then unconfigure the device.
+
+                Writing -1 will always unconfigure the device.
+Users:
+                libusb
+
+What:           /sys/bus/usb/devices/.../busnum
+KernelVersion:  2.6.22
+Description:
+                Bus-number of the USB-bus the device is connected to.
+Users:
+                libusb
+
+What:           /sys/bus/usb/devices/.../descriptors
+KernelVersion:  2.6.26
+Description:
+                Binary file containing cached descriptors of the device. The
+                binary data consists of the device descriptor followed by the
+                descriptors for each configuration of the device.
+                Note that the wTotalLength of the config descriptors can not
+                be trusted, as the device may have a smaller config descriptor
+                than it advertises. The bLength field of each (sub) descriptor
+                can be trusted, and can be used to seek forward one (sub)
+                descriptor at a time until the next config descriptor is found.
+                All descriptors read from this file are in bus-endian format
+Users:
+                libusb
+
+What:           /sys/bus/usb/devices/.../speed
+KernelVersion:  since at least 2.6.18
+Description:
+                Speed the device is connected with to the usb-host in
+                Mbit / second. IE one of 1.5 / 12 / 480 / 5000.
+Users:
+                libusb