--- /dev/null
+What: /sys/bus/usb/devices/.../power/persist
+Date: May 2007
+KernelVersion: 2.6.23
+Contact: Alan Stern <stern@rowland.harvard.edu>
+Description:
+ USB device directories can 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. For
+ hubs this facility is always enabled and their device
+ directories will not contain this file.
+
+ 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 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 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
Code Review / kvmfornfv.git / blobdiff