Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 607 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-bus-usb b/Documentation/ABI/testing/sysfs-bus-usb
new file mode 100644
index 000000000..baf4bf6d3
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-bus-usb
@@ -0,0 +1,607 @@
+What:		/sys/bus/usb/devices/<INTERFACE>/authorized
+Date:		August 2015
+Description:
+		This allows to authorize (1) or deauthorize (0)
+		individual interfaces instead a whole device
+		in contrast to the device authorization.
+		If a deauthorized interface will be authorized
+		so the driver probing must be triggered manually
+		by writing INTERFACE to /sys/bus/usb/drivers_probe
+		This allows to avoid side-effects with drivers
+		that need multiple interfaces.
+
+		A deauthorized interface cannot be probed or claimed.
+
+What:		/sys/bus/usb/devices/usbX/interface_authorized_default
+Date:		August 2015
+Description:
+		This is used as value that determines if interfaces
+		would be authorized by default.
+		The value can be 1 or 0. It's by default 1.
+
+What:		/sys/bus/usb/device/.../authorized
+Date:		July 2008
+KernelVersion:	2.6.26
+Contact:	David Vrabel <david.vrabel@csr.com>
+Description:
+		Authorized devices are available for use by device
+		drivers, non-authorized one are not.  By default, wired
+		USB devices are authorized.
+
+What:		/sys/bus/usb/drivers/.../new_id
+Date:		October 2011
+Contact:	linux-usb@vger.kernel.org
+Description:
+		Writing a device ID to this file will attempt to
+		dynamically add a new device ID to a USB device driver.
+		This may allow the driver to support more hardware than
+		was included in the driver's static device ID support
+		table at compile time. The format for the device ID is:
+		idVendor idProduct bInterfaceClass RefIdVendor RefIdProduct
+		The vendor ID and device ID fields are required, the
+		rest is optional. The `Ref*` tuple can be used to tell the
+		driver to use the same driver_data for the new device as
+		it is used for the reference device.
+		Upon successfully adding an ID, the driver will probe
+		for the device and attempt to bind to it.  For example::
+
+		  # echo "8086 10f5" > /sys/bus/usb/drivers/foo/new_id
+
+		Here add a new device (0458:7045) using driver_data from
+		an already supported device (0458:704c)::
+
+		  # echo "0458 7045 0 0458 704c" > /sys/bus/usb/drivers/foo/new_id
+
+		Reading from this file will list all dynamically added
+		device IDs in the same format, with one entry per
+		line. For example::
+
+		  # cat /sys/bus/usb/drivers/foo/new_id
+		  8086 10f5
+		  dead beef 06
+		  f00d cafe
+
+		The list will be truncated at PAGE_SIZE bytes due to
+		sysfs restrictions.
+
+What:		/sys/bus/usb-serial/drivers/.../new_id
+Date:		October 2011
+Contact:	linux-usb@vger.kernel.org
+Description:
+		For serial USB drivers, this attribute appears under the
+		extra bus folder "usb-serial" in sysfs; apart from that
+		difference, all descriptions from the entry
+		"/sys/bus/usb/drivers/.../new_id" apply.
+
+What:		/sys/bus/usb/drivers/.../remove_id
+Date:		November 2009
+Contact:	CHENG Renquan <rqcheng@smu.edu.sg>
+Description:
+		Writing a device ID to this file will remove an ID
+		that was dynamically added via the new_id sysfs entry.
+		The format for the device ID is:
+		idVendor idProduct.	After successfully
+		removing an ID, the driver will no longer support the
+		device.  This is useful to ensure auto probing won't
+		match the driver to the device.  For example:
+		# echo "046d c315" > /sys/bus/usb/drivers/foo/remove_id
+
+		Reading from this file will list the dynamically added
+		device IDs, exactly like reading from the entry
+		"/sys/bus/usb/drivers/.../new_id"
+
+What:		/sys/bus/usb/devices/.../power/usb2_hardware_lpm
+Date:		September 2011
+Contact:	Andiry Xu <andiry.xu@amd.com>
+Description:
+		If CONFIG_PM is set and a USB 2.0 lpm-capable device is plugged
+		in to a xHCI host which support link PM, it will perform a LPM
+		test; if the test is passed and host supports USB2 hardware LPM
+		(xHCI 1.0 feature), USB2 hardware LPM will be enabled for the
+		device and the USB device directory will contain a file named
+		power/usb2_hardware_lpm.  The file holds a string value (enable
+		or disable) indicating whether or not USB2 hardware LPM is
+		enabled for the device. Developer can write y/Y/1 or n/N/0 to
+		the file to enable/disable the feature.
+
+What:		/sys/bus/usb/devices/.../power/usb3_hardware_lpm_u1
+		/sys/bus/usb/devices/.../power/usb3_hardware_lpm_u2
+Date:		November 2015
+Contact:	Kevin Strasser <kevin.strasser@linux.intel.com>
+		Lu Baolu <baolu.lu@linux.intel.com>
+Description:
+		If CONFIG_PM is set and a USB 3.0 lpm-capable device is plugged
+		in to a xHCI host which supports link PM, it will check if U1
+		and U2 exit latencies have been set in the BOS descriptor; if
+		the check is passed and the host supports USB3 hardware LPM,
+		USB3 hardware LPM will be enabled for the device and the USB
+		device directory will contain two files named
+		power/usb3_hardware_lpm_u1 and power/usb3_hardware_lpm_u2. These
+		files hold a string value (enable or disable) indicating whether
+		or not USB3 hardware LPM U1 or U2 is enabled for the device.
+
+What:		/sys/bus/usb/devices/.../ltm_capable
+Date:		July 2012
+Contact:	Sarah Sharp <sarah.a.sharp@linux.intel.com>
+Description:
+		USB 3.0 devices may optionally support Latency Tolerance
+		Messaging (LTM).  They indicate their support by setting a bit
+		in the bmAttributes field of their SuperSpeed BOS descriptors.
+		If that bit is set for the device, ltm_capable will read "yes".
+		If the device doesn't support LTM, the file will read "no".
+		The file will be present for all speeds of USB devices, and will
+		always read "no" for USB 1.1 and USB 2.0 devices.
+
+What:		/sys/bus/usb/devices/<INTERFACE>/wireless_status
+Date:		February 2023
+Contact:	Bastien Nocera <hadess@hadess.net>
+Description:
+		Some USB devices use a USB receiver dongle to communicate
+		wirelessly with their device using proprietary protocols. This
+		attribute allows user-space to know whether the device is
+		connected to its receiver dongle, and, for example, consider
+		the device to be absent when choosing whether to show the
+		device's battery, show a headset in a list of outputs, or show
+		an on-screen keyboard if the only wireless keyboard is
+		turned off.
+		This attribute is not to be used to replace protocol specific
+		statuses available in WWAN, WLAN/Wi-Fi, Bluetooth, etc.
+		If the device does not use a receiver dongle with a wireless
+		device, then this attribute will not exist.
+
+What:		/sys/bus/usb/devices/.../<hub_interface>/port<X>
+Date:		August 2012
+Contact:	Lan Tianyu <tianyu.lan@intel.com>
+Description:
+		The /sys/bus/usb/devices/.../<hub_interface>/port<X>
+		is usb port device's sysfs directory.
+
+What:		/sys/bus/usb/devices/.../<hub_interface>/port<X>/connect_type
+Date:		January 2013
+Contact:	Lan Tianyu <tianyu.lan@intel.com>
+Description:
+		Some platforms provide usb port connect types through ACPI.
+		This attribute is to expose these information to user space.
+		The file will read "hotplug", "hardwired" and "not used" if the
+		information is available, and "unknown" otherwise.
+
+What:		/sys/bus/usb/devices/.../<hub_interface>/port<X>/location
+Date:		October 2018
+Contact:	Bjørn Mork <bjorn@mork.no>
+Description:
+		Some platforms provide usb port physical location through
+		firmware. This is used by the kernel to pair up logical ports
+		mapping to the same physical connector. The attribute exposes the
+		raw location value as a hex integer.
+
+
+What:		/sys/bus/usb/devices/.../<hub_interface>/port<X>/quirks
+Date:		May 2018
+Contact:	Nicolas Boichat <drinkcat@chromium.org>
+Description:
+		In some cases, we care about time-to-active for devices
+		connected on a specific port (e.g. non-standard USB port like
+		pogo pins), where the device to be connected is known in
+		advance, and behaves well according to the specification.
+		This attribute is a bit-field that controls the behavior of
+		a specific port:
+
+		 - Bit 0 of this field selects the "old" enumeration scheme,
+		   as it is considerably faster (it only causes one USB reset
+		   instead of 2).
+
+		   The old enumeration scheme can also be selected globally
+		   using /sys/module/usbcore/parameters/old_scheme_first, but
+		   it is often not desirable as the new scheme was introduced to
+		   increase compatibility with more devices.
+		 - Bit 1 reduces TRSTRCY to the 10 ms that are required by the
+		   USB 2.0 specification, instead of the 50 ms that are normally
+		   used to help make enumeration work better on some high speed
+		   devices.
+
+What:		/sys/bus/usb/devices/.../<hub_interface>/port<X>/over_current_count
+Date:		February 2018
+Contact:	Richard Leitner <richard.leitner@skidata.com>
+Description:
+		Most hubs are able to detect over-current situations on their
+		ports and report them to the kernel. This attribute is to expose
+		the number of over-current situation occurred on a specific port
+		to user space. This file will contain an unsigned 32 bit value
+		which wraps to 0 after its maximum is reached. This file supports
+		poll() for monitoring changes to this value in user space.
+
+		Any time this value changes the corresponding hub device will send a
+		udev event with the following attributes::
+
+		  OVER_CURRENT_PORT=/sys/bus/usb/devices/.../<hub_interface>/port<X>
+		  OVER_CURRENT_COUNT=[current value of this sysfs attribute]
+
+What:		/sys/bus/usb/devices/.../<hub_interface>/port<X>/usb3_lpm_permit
+Date:		November 2015
+Contact:	Lu Baolu <baolu.lu@linux.intel.com>
+Description:
+		Some USB3.0 devices are not friendly to USB3 LPM.  usb3_lpm_permit
+		attribute allows enabling/disabling usb3 lpm of a port. It takes
+		effect both before and after a usb device is enumerated. Supported
+		values are "0" if both u1 and u2 are NOT permitted, "u1" if only u1
+		is permitted, "u2" if only u2 is permitted, "u1_u2" if both u1 and
+		u2 are permitted.
+
+What:		/sys/bus/usb/devices/.../<hub_interface>/port<X>/connector
+Date:		December 2021
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		Link to the USB Type-C connector when available. This link is
+		only created when USB Type-C Connector Class is enabled, and
+		only if the system firmware is capable of describing the
+		connection between a port and its connector.
+
+What:		/sys/bus/usb/devices/.../<hub_interface>/port<X>/disable
+Date:		June 2022
+Contact:	Michael Grzeschik <m.grzeschik@pengutronix.de>
+Description:
+		This file controls the state of a USB port, including
+		Vbus power output (but only on hubs that support
+		power switching -- most hubs don't support it). If
+		a port is disabled, the port is unusable: Devices
+		attached to the port will not be detected, initialized,
+		or enumerated.
+
+What:		/sys/bus/usb/devices/.../<hub_interface>/port<X>/early_stop
+Date:		Sep 2022
+Contact:	Ray Chi <raychi@google.com>
+Description:
+		Some USB hosts have some watchdog mechanisms so that the device
+		may enter ramdump if it takes a long time during port initialization.
+		This attribute allows each port just has two attempts so that the
+		port initialization will be failed quickly. In addition, if a port
+		which is marked with early_stop has failed to initialize, it will ignore
+		all future connections until this attribute is clear.
+
+What:		/sys/bus/usb/devices/.../<hub_interface>/port<X>/state
+Date:		June 2023
+Contact:	Roy Luo <royluo@google.com>
+Description:
+		Indicates current state of the USB device attached to the port.
+		Valid states are: 'not-attached', 'attached', 'powered',
+		'reconnecting', 'unauthenticated', 'default', 'addressed',
+		'configured', and 'suspended'. This file supports poll() to
+		monitor the state change from user space.
+
+What:		/sys/bus/usb/devices/.../power/usb2_lpm_l1_timeout
+Date:		May 2013
+Contact:	Mathias Nyman <mathias.nyman@linux.intel.com>
+Description:
+		USB 2.0 devices may support hardware link power management (LPM)
+		L1 sleep state. The usb2_lpm_l1_timeout attribute allows
+		tuning the timeout for L1 inactivity timer (LPM timer), e.g.
+		needed inactivity time before host requests the device to go to L1 sleep.
+		Useful for power management tuning.
+		Supported values are 0 - 65535 microseconds.
+
+What:		/sys/bus/usb/devices/.../power/usb2_lpm_besl
+Date:		May 2013
+Contact:	Mathias Nyman <mathias.nyman@linux.intel.com>
+Description:
+		USB 2.0 devices that support hardware link power management (LPM)
+		L1 sleep state now use a best effort service latency value (BESL) to
+		indicate the best effort to resumption of service to the device after the
+		initiation of the resume event.
+		If the device does not have a preferred besl value then the host can select
+		one instead. This usb2_lpm_besl attribute allows to tune the host selected besl
+		value in order to tune power saving and service latency.
+
+		Supported values are 0 - 15.
+		More information on how besl values map to microseconds can be found in
+		USB 2.0 ECN Errata for Link Power Management, section 4.10
+
+What:		/sys/bus/usb/devices/.../rx_lanes
+Date:		March 2018
+Contact:	Mathias Nyman <mathias.nyman@linux.intel.com>
+Description:
+		Number of rx lanes the device is using.
+		USB 3.2 adds Dual-lane support, 2 rx and 2 tx lanes over Type-C.
+		Inter-Chip SSIC devices support asymmetric lanes up to 4 lanes per
+		direction. Devices before USB 3.2 are single lane (rx_lanes = 1)
+
+What:		/sys/bus/usb/devices/.../tx_lanes
+Date:		March 2018
+Contact:	Mathias Nyman <mathias.nyman@linux.intel.com>
+Description:
+		Number of tx lanes the device is using.
+		USB 3.2 adds Dual-lane support, 2 rx and 2 tx -lanes over Type-C.
+		Inter-Chip SSIC devices support asymmetric lanes up to 4 lanes per
+		direction. Devices before USB 3.2 are single lane (tx_lanes = 1)
+
+What:		/sys/bus/usb/devices/.../typec
+Date:		November 2023
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		Symlink to the USB Type-C partner device. USB Type-C partner
+		represents the component that communicates over the
+		Configuration Channel (CC signal on USB Type-C connectors and
+		cables) with the local port.
+
+What:		/sys/bus/usb/devices/usbX/bAlternateSetting
+Description:
+		The current interface alternate setting number, in decimal.
+
+		See USB specs for its meaning.
+
+What:		/sys/bus/usb/devices/usbX/bcdDevice
+Description:
+		The device's release number, in hexadecimal.
+
+		See USB specs for its meaning.
+
+What:		/sys/bus/usb/devices/usbX/bConfigurationValue
+Description:
+		While a USB device typically have just one configuration
+		setting, some devices support multiple configurations.
+
+		This value shows the current configuration, in decimal.
+
+		Changing its value will change the device's configuration
+		to another setting.
+
+		The number of configurations supported by a device is at:
+
+			/sys/bus/usb/devices/usbX/bNumConfigurations
+
+		See USB specs for its meaning.
+
+What:		/sys/bus/usb/devices/usbX/bDeviceClass
+Description:
+		Class code of the device, in hexadecimal.
+
+		See USB specs for its meaning.
+
+What:		/sys/bus/usb/devices/usbX/bDeviceProtocol
+Description:
+		Protocol code of the device, in hexadecimal.
+
+		See USB specs for its meaning.
+
+What:		/sys/bus/usb/devices/usbX/bDeviceSubClass
+Description:
+		Subclass code of the device, in hexadecimal.
+
+		See USB specs for its meaning.
+
+What:		/sys/bus/usb/devices/usbX/bInterfaceClass
+Description:
+		Class code of the interface, in hexadecimal.
+
+		See USB specs for its meaning.
+
+What:		/sys/bus/usb/devices/usbX/bInterfaceNumber
+Description:
+		Interface number, in hexadecimal.
+
+		See USB specs for its meaning.
+
+What:		/sys/bus/usb/devices/usbX/bInterfaceProtocol
+Description:
+		Protocol code of the interface, in hexadecimal.
+
+		See USB specs for its meaning.
+
+What:		/sys/bus/usb/devices/usbX/bInterfaceSubClass
+Description:
+		Subclass code of the interface, in hexadecimal.
+
+		See USB specs for its meaning.
+
+What:		/sys/bus/usb/devices/usbX/bmAttributes
+Description:
+		Attributes of the current configuration, in hexadecimal.
+
+		See USB specs for its meaning.
+
+What:		/sys/bus/usb/devices/usbX/bMaxPacketSize0
+Description:
+		Maximum endpoint 0 packet size, in decimal.
+
+		See USB specs for its meaning.
+
+What:		/sys/bus/usb/devices/usbX/bMaxPower
+Description:
+		Maximum power consumption of the active configuration of
+		the device, in miliamperes.
+
+What:		/sys/bus/usb/devices/usbX/bNumConfigurations
+Description:
+		Number of the possible configurations of the device, in
+		decimal. The current configuration is controlled via:
+
+			/sys/bus/usb/devices/usbX/bConfigurationValue
+
+		See USB specs for its meaning.
+
+What:		/sys/bus/usb/devices/usbX/bNumEndpoints
+Description:
+		Number of endpoints used on this interface, in hexadecimal.
+
+		See USB specs for its meaning.
+
+What:		/sys/bus/usb/devices/usbX/bNumInterfaces
+Description:
+		Number of interfaces on this device, in decimal.
+
+What:		/sys/bus/usb/devices/usbX/busnum
+Description:
+		Number of the bus.
+
+What:		/sys/bus/usb/devices/usbX/configuration
+Description:
+		Contents of the string descriptor associated with the
+		current configuration. It may include the firmware version
+		of a device and/or its serial number.
+
+What:		/sys/bus/usb/devices/usbX/descriptors
+Description:
+		Contains the interface descriptors, in binary.
+
+What:		/sys/bus/usb/devices/usbX/bos_descriptors
+Date:		March 2024
+Contact:	Elbert Mai <code@elbertmai.com>
+Description:
+		Binary file containing the cached binary device object store (BOS)
+		of the device. This consists of the BOS descriptor followed by the
+		set of device capability descriptors. All descriptors read from
+		this file are in bus-endian format. Note that the kernel will not
+		request the BOS from a device if its bcdUSB is less than 0x0201.
+
+What:		/sys/bus/usb/devices/usbX/idProduct
+Description:
+		Product ID, in hexadecimal.
+
+What:		/sys/bus/usb/devices/usbX/idVendor
+Description:
+		Vendor ID, in hexadecimal.
+
+What:		/sys/bus/usb/devices/usbX/devspec
+Description:
+		Displays the Device Tree Open Firmware node of the interface.
+
+What:		/sys/bus/usb/devices/usbX/avoid_reset_quirk
+Description:
+		Most devices have this set to zero.
+
+		If the value is 1, enable a USB quirk that prevents this
+		device to use reset.
+
+		(read/write)
+
+What:		/sys/bus/usb/devices/usbX/devnum
+Description:
+		USB interface device number, in decimal.
+
+What:		/sys/bus/usb/devices/usbX/devpath
+Description:
+		String containing the USB interface device path.
+
+What:		/sys/bus/usb/devices/usbX/manufacturer
+Description:
+		Vendor specific string containing the name of the
+		manufacturer of the device.
+
+What:		/sys/bus/usb/devices/usbX/maxchild
+Description:
+		Number of ports of an USB hub
+
+What:		/sys/bus/usb/devices/usbX/persist
+Description:
+		Keeps the device even if it gets disconnected.
+
+What:		/sys/bus/usb/devices/usbX/product
+Description:
+		Vendor specific string containing the name of the
+		device's product.
+
+What:		/sys/bus/usb/devices/usbX/speed
+Description:
+		Shows the device's max speed, according to the USB version,
+		in Mbps.
+		Can be:
+
+			=======		====================
+			Unknown		speed unknown
+			1.5		Low speed
+			15		Full speed
+			480		High Speed
+			5000		Super Speed
+			10000		Super Speed+
+			20000		Super Speed+ Gen 2x2
+			=======		====================
+
+What:		/sys/bus/usb/devices/usbX/supports_autosuspend
+Description:
+		Returns 1 if the device doesn't support autosuspend.
+		Otherwise, returns 0.
+
+What:		/sys/bus/usb/devices/usbX/urbnum
+Description:
+		Number of URBs submitted for the whole device.
+
+What:		/sys/bus/usb/devices/usbX/version
+Description:
+		String containing the USB device version, as encoded
+		at the BCD descriptor.
+
+What:		/sys/bus/usb/devices/usbX/power/autosuspend
+Description:
+		Time in milliseconds for the device to autosuspend. If the
+		value is negative, then autosuspend is prevented.
+
+		(read/write)
+
+What:		/sys/bus/usb/devices/usbX/power/active_duration
+Description:
+		The total time the device has not been suspended.
+
+What:		/sys/bus/usb/devices/usbX/power/connected_duration
+Description:
+		The total time (in msec) that the device has been connected.
+
+What:		/sys/bus/usb/devices/usbX/power/level
+Description:
+
+What:		/sys/bus/usb/devices/usbX/ep_<N>/bEndpointAddress
+Description:
+		The address of the endpoint described by this descriptor,
+		in hexadecimal. The endpoint direction on this bitmapped field
+		is also shown at:
+
+			/sys/bus/usb/devices/usbX/ep_<N>/direction
+
+		See USB specs for its meaning.
+
+What:		/sys/bus/usb/devices/usbX/ep_<N>/bInterval
+Description:
+		The interval of the endpoint as described on its descriptor,
+		in hexadecimal. The actual interval depends on the version
+		of the USB. Also shown in time units at
+		/sys/bus/usb/devices/usbX/ep_<N>/interval.
+
+What:		/sys/bus/usb/devices/usbX/ep_<N>/bLength
+Description:
+		Number of bytes of the endpoint descriptor, in hexadecimal.
+
+What:		/sys/bus/usb/devices/usbX/ep_<N>/bmAttributes
+Description:
+		Attributes which apply to the endpoint as described on its
+		descriptor, in hexadecimal. The endpoint type on this
+		bitmapped field is also shown at:
+
+			/sys/bus/usb/devices/usbX/ep_<N>/type
+
+		See USB specs for its meaning.
+
+What:		/sys/bus/usb/devices/usbX/ep_<N>/direction
+Description:
+		Direction of the endpoint. Can be:
+
+		    - both (on control endpoints)
+		    - in
+		    - out
+
+What:		/sys/bus/usb/devices/usbX/ep_<N>/interval
+Description:
+		Interval for polling endpoint for data transfers, in
+		milisseconds or microseconds.
+
+What:		/sys/bus/usb/devices/usbX/ep_<N>/type
+Description:
+		Descriptor type. Can be:
+
+		    - Control
+		    - Isoc
+		    - Bulk
+		    - Interrupt
+		    - unknown
+
+What:		/sys/bus/usb/devices/usbX/ep_<N>/wMaxPacketSize
+Description:
+		Maximum packet size this endpoint is capable of
+		sending or receiving, in hexadecimal.