error-codes.rst: convert to ReST and add to driver-api book (360a7b5f) · Commits · jan.koester / Linux

Documentation/driver-api/usb/error-codes.rst

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		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.

		``-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.
		======================= ==============================================

Documentation/driver-api/usb/index.rst

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		@@ -11,6 +11,7 @@ Linux USB API
		callbacks
		dma
		power-management
		error-codes
		writing_usb_driver
		writing_musb_glue_layer

Documentation/usb/error-codes.txt

deleted100644 → 0

+0 −175

Original line number	Diff line number	Diff line
		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 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.

		-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 usb_unlink_urb

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

		-EPROTO (, *) a) bitstuff error
		b) no response packet received within the
		prescribed bus turn-around time
		c) unknown USB error

		-EILSEQ (, *) 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 (**) 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 (**) Endpoint stalled. For non-control endpoints,
		reset this status with 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 (*) 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 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.


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

		(**) 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 *
		* (expect also other submit and transfer status codes) *
		**************************************************************************

		usb_register():
		-EINVAL error during registering new driver

		usb_get_/usb_set_():
		usb_control_msg():
		usb_bulk_msg():
		-ETIMEDOUT Timeout expired before the transfer completed.