Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 360a7b5f authored by Mauro Carvalho Chehab's avatar Mauro Carvalho Chehab Committed by Jonathan Corbet
Browse files

error-codes.rst: convert to ReST and add to driver-api book 



This document describe some USB core features. Add it to the
driver-api book.

Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@s-opensource.com>
Acked-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarJonathan Corbet <corbet@lwn.net>
parent 2a373331

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

0 → 100644
+205 −0
Original line number Diff line number Diff line 
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

+1 −0
Original line number Diff line number Diff line
@@ -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.