Documentation/driver-api/usb/error-codes.rst - linux - Git at Google

 .. _usb-error-codes:

 USB Error codes
 ~~~~~~~~~~~~~~~

 :Revised: 2004-Oct-21

 This is the documentation of (hopefully) all possible error codes (and
 their interpretation) that can be returned from usbcore.

 Some of them are returned by the Host Controller Drivers (HCDs), which
 device drivers only see through usbcore.  As a rule, all the HCDs should
 behave the same except for transfer speed dependent behaviors and the
 way certain faults are reported.


 Error codes returned by :c:func:`usb_submit_urb`
 ================================================

 Non-USB-specific:


 =============== ===============================================
 0		URB submission went fine

 ``-ENOMEM``	no memory for allocation of internal structures
 =============== ===============================================

 USB-specific:

 =======================	=======================================================
 ``-EBUSY``		The URB is already active.

 ``-ENODEV``		specified USB-device or bus doesn't exist

 ``-ENOENT``		specified interface or endpoint does not exist or
 			is not enabled

 ``-ENXIO``		host controller driver does not support queuing of
 			this type of urb.  (treat as a host controller bug.)

 ``-EINVAL``		a) Invalid transfer type specified (or not supported)
 			b) Invalid or unsupported periodic transfer interval
 			c) ISO: attempted to change transfer interval
 			d) ISO: ``number_of_packets`` is < 0
 			e) various other cases

 ``-EXDEV``		ISO: ``URB_ISO_ASAP`` wasn't specified and all the
 			frames the URB would be scheduled in have already
 			expired.

 ``-EFBIG``		Host controller driver can't schedule that many ISO
 			frames.

 ``-EPIPE``		The pipe type specified in the URB doesn't match the
 			endpoint's actual type.

 ``-EMSGSIZE``		(a) endpoint maxpacket size is zero; it is not usable
 			    in the current interface altsetting.
 			(b) ISO packet is larger than the endpoint maxpacket.
 			(c) requested data transfer length is invalid: negative
 			    or too large for the host controller.

 ``-EBADR``		The wLength value in a control URB's setup packet does
 			not match the URB's transfer_buffer_length.

 ``-ENOSPC``		This request would overcommit the usb bandwidth reserved
 			for periodic transfers (interrupt, isochronous).

 ``-ESHUTDOWN``		The device or host controller has been disabled due to
 			some problem that could not be worked around.

 ``-EPERM``		Submission failed because ``urb->reject`` was set.

 ``-EHOSTUNREACH``	URB was rejected because the device is suspended.

 ``-ENOEXEC``		A control URB doesn't contain a Setup packet.
 =======================	=======================================================

 Error codes returned by ``in urb->status`` or in ``iso_frame_desc[n].status`` (for ISO)
 =======================================================================================

 USB device drivers may only test urb status values in completion handlers.
 This is because otherwise there would be a race between HCDs updating
 these values on one CPU, and device drivers testing them on another CPU.

 A transfer's actual_length may be positive even when an error has been
 reported.  That's because transfers often involve several packets, so that
 one or more packets could finish before an error stops further endpoint I/O.

 For isochronous URBs, the urb status value is non-zero only if the URB is
 unlinked, the device is removed, the host controller is disabled, or the total
 transferred length is less than the requested length and the
 ``URB_SHORT_NOT_OK`` flag is set.  Completion handlers for isochronous URBs
 should only see ``urb->status`` set to zero, ``-ENOENT``, ``-ECONNRESET``,
 ``-ESHUTDOWN``, or ``-EREMOTEIO``. Individual frame descriptor status fields
 may report more status codes.


 ===============================	===============================================
 0				Transfer completed successfully

 ``-ENOENT``			URB was synchronously unlinked by
 				:c:func:`usb_unlink_urb`

 ``-EINPROGRESS``		URB still pending, no results yet
 				(That is, if drivers see this it's a bug.)

 ``-EPROTO`` [#f1]_, [#f2]_	a) bitstuff error
 				b) no response packet received within the
 				   prescribed bus turn-around time
 				c) unknown USB error

 ``-EILSEQ`` [#f1]_, [#f2]_	a) CRC mismatch
 				b) no response packet received within the
 				   prescribed bus turn-around time
 				c) unknown USB error

 				Note that often the controller hardware does
 				not distinguish among cases a), b), and c), so
 				a driver cannot tell whether there was a
 				protocol error, a failure to respond (often
 				caused by device disconnect), or some other
 				fault.

 ``-ETIME`` [#f2]_		No response packet received within the
 				prescribed bus turn-around time.  This error
 				may instead be reported as
 				``-EPROTO`` or ``-EILSEQ``.

 ``-ETIMEDOUT``			Synchronous USB message functions use this code
 				to indicate timeout expired before the transfer
 				completed, and no other error was reported
 				by HC.

 ``-EPIPE`` [#f2]_		Endpoint stalled.  For non-control endpoints,
 				reset this status with
 				:c:func:`usb_clear_halt`.

 ``-ECOMM``			During an IN transfer, the host controller
 				received data from an endpoint faster than it
 				could be written to system memory

 ``-ENOSR``			During an OUT transfer, the host controller
 				could not retrieve data from system memory fast
 				enough to keep up with the USB data rate

 ``-EOVERFLOW`` [#f1]_		The amount of data returned by the endpoint was
 				greater than either the max packet size of the
 				endpoint or the remaining buffer size.
 				"Babble".

 ``-EREMOTEIO``			The data read from the endpoint did not fill
 				the specified buffer, and ``URB_SHORT_NOT_OK``
 				was set in ``urb->transfer_flags``.

 ``-ENODEV``			Device was removed.  Often preceded by a burst
 				of other errors, since the hub driver doesn't
 				detect device removal events immediately.

 ``-EXDEV``			ISO transfer only partially completed
 				(only set in ``iso_frame_desc[n].status``,
 				not ``urb->status``)

 ``-EINVAL``			ISO madness, if this happens: Log off and
 				go home

 ``-ECONNRESET``			URB was asynchronously unlinked by
 				:c:func:`usb_unlink_urb`

 ``-ESHUTDOWN``			The device or host controller has been
 				disabled due to some problem that could not
 				be worked around, such as a physical
 				disconnect.
 ===============================	===============================================


 .. [#f1]

    Error codes like ``-EPROTO``, ``-EILSEQ`` and ``-EOVERFLOW`` normally
    indicate hardware problems such as bad devices (including firmware)
    or cables.

 .. [#f2]

    This is also one of several codes that different kinds of host
    controller use to indicate a transfer has failed because of device
    disconnect.  In the interval before the hub driver starts disconnect
    processing, devices may receive such fault reports for every request.


 Error codes returned by usbcore-functions
 =========================================

 .. note:: expect also other submit and transfer status codes

 :c:func:`usb_register`:

 ======================= ===================================
 ``-EINVAL``		error during registering new driver
 ======================= ===================================

 ``usb_get_*/usb_set_*()``,
 :c:func:`usb_control_msg`,
 :c:func:`usb_bulk_msg()`:

 ======================= ==============================================
 ``-ETIMEDOUT``		Timeout expired before the transfer completed.
 ======================= ==============================================
	.. _usb-error-codes:

	USB Error codes
	~~~~~~~~~~~~~~~

	:Revised: 2004-Oct-21

	This is the documentation of (hopefully) all possible error codes (and
	their interpretation) that can be returned from usbcore.

	Some of them are returned by the Host Controller Drivers (HCDs), which
	device drivers only see through usbcore. As a rule, all the HCDs should
	behave the same except for transfer speed dependent behaviors and the
	way certain faults are reported.


	Error codes returned by :c:func:`usb_submit_urb`
	================================================

	Non-USB-specific:


	=============== ===============================================
	0 URB submission went fine

	``-ENOMEM`` no memory for allocation of internal structures
	=============== ===============================================

	USB-specific:

	======================= =======================================================
	``-EBUSY`` The URB is already active.

	``-ENODEV`` specified USB-device or bus doesn't exist

	``-ENOENT`` specified interface or endpoint does not exist or
	is not enabled

	``-ENXIO`` host controller driver does not support queuing of
	this type of urb. (treat as a host controller bug.)

	``-EINVAL`` a) Invalid transfer type specified (or not supported)
	b) Invalid or unsupported periodic transfer interval
	c) ISO: attempted to change transfer interval
	d) ISO: ``number_of_packets`` is < 0
	e) various other cases

	``-EXDEV`` ISO: ``URB_ISO_ASAP`` wasn't specified and all the
	frames the URB would be scheduled in have already
	expired.

	``-EFBIG`` Host controller driver can't schedule that many ISO
	frames.

	``-EPIPE`` The pipe type specified in the URB doesn't match the
	endpoint's actual type.

	``-EMSGSIZE`` (a) endpoint maxpacket size is zero; it is not usable
	in the current interface altsetting.
	(b) ISO packet is larger than the endpoint maxpacket.
	(c) requested data transfer length is invalid: negative
	or too large for the host controller.

	``-EBADR`` The wLength value in a control URB's setup packet does
	not match the URB's transfer_buffer_length.

	``-ENOSPC`` This request would overcommit the usb bandwidth reserved
	for periodic transfers (interrupt, isochronous).

	``-ESHUTDOWN`` The device or host controller has been disabled due to
	some problem that could not be worked around.

	``-EPERM`` Submission failed because ``urb->reject`` was set.

	``-EHOSTUNREACH`` URB was rejected because the device is suspended.

	``-ENOEXEC`` A control URB doesn't contain a Setup packet.
	======================= =======================================================

	Error codes returned by ``in urb->status`` or in ``iso_frame_desc[n].status`` (for ISO)
	=======================================================================================

	USB device drivers may only test urb status values in completion handlers.
	This is because otherwise there would be a race between HCDs updating
	these values on one CPU, and device drivers testing them on another CPU.

	A transfer's actual_length may be positive even when an error has been
	reported. That's because transfers often involve several packets, so that
	one or more packets could finish before an error stops further endpoint I/O.

	For isochronous URBs, the urb status value is non-zero only if the URB is
	unlinked, the device is removed, the host controller is disabled, or the total
	transferred length is less than the requested length and the
	``URB_SHORT_NOT_OK`` flag is set. Completion handlers for isochronous URBs
	should only see ``urb->status`` set to zero, ``-ENOENT``, ``-ECONNRESET``,
	``-ESHUTDOWN``, or ``-EREMOTEIO``. Individual frame descriptor status fields
	may report more status codes.


	=============================== ===============================================
	0 Transfer completed successfully

	``-ENOENT`` URB was synchronously unlinked by
	:c:func:`usb_unlink_urb`

	``-EINPROGRESS`` URB still pending, no results yet
	(That is, if drivers see this it's a bug.)

	``-EPROTO`` [#f1]_, [#f2]_ a) bitstuff error
	b) no response packet received within the
	prescribed bus turn-around time
	c) unknown USB error

	``-EILSEQ`` [#f1]_, [#f2]_ a) CRC mismatch
	b) no response packet received within the
	prescribed bus turn-around time
	c) unknown USB error

	Note that often the controller hardware does
	not distinguish among cases a), b), and c), so
	a driver cannot tell whether there was a
	protocol error, a failure to respond (often
	caused by device disconnect), or some other
	fault.

	``-ETIME`` [#f2]_ No response packet received within the
	prescribed bus turn-around time. This error
	may instead be reported as
	``-EPROTO`` or ``-EILSEQ``.

	``-ETIMEDOUT`` Synchronous USB message functions use this code
	to indicate timeout expired before the transfer
	completed, and no other error was reported
	by HC.

	``-EPIPE`` [#f2]_ Endpoint stalled. For non-control endpoints,
	reset this status with
	:c:func:`usb_clear_halt`.

	``-ECOMM`` During an IN transfer, the host controller
	received data from an endpoint faster than it
	could be written to system memory

	``-ENOSR`` During an OUT transfer, the host controller
	could not retrieve data from system memory fast
	enough to keep up with the USB data rate

	``-EOVERFLOW`` [#f1]_ The amount of data returned by the endpoint was
	greater than either the max packet size of the
	endpoint or the remaining buffer size.
	"Babble".

	``-EREMOTEIO`` The data read from the endpoint did not fill
	the specified buffer, and ``URB_SHORT_NOT_OK``
	was set in ``urb->transfer_flags``.

	``-ENODEV`` Device was removed. Often preceded by a burst
	of other errors, since the hub driver doesn't
	detect device removal events immediately.

	``-EXDEV`` ISO transfer only partially completed
	(only set in ``iso_frame_desc[n].status``,
	not ``urb->status``)

	``-EINVAL`` ISO madness, if this happens: Log off and
	go home

	``-ECONNRESET`` URB was asynchronously unlinked by
	:c:func:`usb_unlink_urb`

	``-ESHUTDOWN`` The device or host controller has been
	disabled due to some problem that could not
	be worked around, such as a physical
	disconnect.
	=============================== ===============================================


	.. [#f1]

	Error codes like ``-EPROTO``, ``-EILSEQ`` and ``-EOVERFLOW`` normally
	indicate hardware problems such as bad devices (including firmware)
	or cables.

	.. [#f2]

	This is also one of several codes that different kinds of host
	controller use to indicate a transfer has failed because of device
	disconnect. In the interval before the hub driver starts disconnect
	processing, devices may receive such fault reports for every request.



	Error codes returned by usbcore-functions
	=========================================

	.. note:: expect also other submit and transfer status codes

	:c:func:`usb_register`:

	======================= ===================================
	``-EINVAL`` error during registering new driver
	======================= ===================================

	``usb_get_/usb_set_()``,
	:c:func:`usb_control_msg`,
	:c:func:`usb_bulk_msg()`:

	======================= ==============================================
	``-ETIMEDOUT`` Timeout expired before the transfer completed.
	======================= ==============================================