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Documentation / usb / error-codes.txt




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Based on kernel version 3.16. Page generated on 2014-08-06 21:41 EST.

1	Revised: 2004-Oct-21
2	
3	This is the documentation of (hopefully) all possible error codes (and
4	their interpretation) that can be returned from usbcore.
5	
6	Some of them are returned by the Host Controller Drivers (HCDs), which
7	device drivers only see through usbcore.  As a rule, all the HCDs should
8	behave the same except for transfer speed dependent behaviors and the
9	way certain faults are reported.
10	
11	
12	**************************************************************************
13	*                   Error codes returned by usb_submit_urb               *
14	**************************************************************************
15	
16	Non-USB-specific:
17	
18	0		URB submission went fine
19	
20	-ENOMEM		no memory for allocation of internal structures	
21	
22	USB-specific:
23	
24	-EBUSY		The URB is already active.
25	
26	-ENODEV		specified USB-device or bus doesn't exist
27	
28	-ENOENT		specified interface or endpoint does not exist or
29			is not enabled
30	
31	-ENXIO		host controller driver does not support queuing of this type
32			of urb.  (treat as a host controller bug.)
33	
34	-EINVAL		a) Invalid transfer type specified (or not supported)
35			b) Invalid or unsupported periodic transfer interval
36			c) ISO: attempted to change transfer interval
37			d) ISO: number_of_packets is < 0
38			e) various other cases
39	
40	-EXDEV		ISO: URB_ISO_ASAP wasn't specified and all the frames
41			the URB would be scheduled in have already expired.
42	
43	-EFBIG		Host controller driver can't schedule that many ISO frames.
44	
45	-EPIPE		The pipe type specified in the URB doesn't match the
46			endpoint's actual type.
47	
48	-EMSGSIZE	(a) endpoint maxpacket size is zero; it is not usable
49			    in the current interface altsetting.
50			(b) ISO packet is larger than the endpoint maxpacket.
51			(c) requested data transfer length is invalid: negative
52			    or too large for the host controller.
53	
54	-ENOSPC		This request would overcommit the usb bandwidth reserved
55			for periodic transfers (interrupt, isochronous).
56	
57	-ESHUTDOWN	The device or host controller has been disabled due to some
58			problem that could not be worked around.
59	
60	-EPERM		Submission failed because urb->reject was set.
61	
62	-EHOSTUNREACH	URB was rejected because the device is suspended.
63	
64	-ENOEXEC	A control URB doesn't contain a Setup packet.
65	
66	
67	**************************************************************************
68	*                   Error codes returned by in urb->status               *
69	*                   or in iso_frame_desc[n].status (for ISO)             *
70	**************************************************************************
71	
72	USB device drivers may only test urb status values in completion handlers.
73	This is because otherwise there would be a race between HCDs updating
74	these values on one CPU, and device drivers testing them on another CPU.
75	
76	A transfer's actual_length may be positive even when an error has been
77	reported.  That's because transfers often involve several packets, so that
78	one or more packets could finish before an error stops further endpoint I/O.
79	
80	For isochronous URBs, the urb status value is non-zero only if the URB is
81	unlinked, the device is removed, the host controller is disabled, or the total
82	transferred length is less than the requested length and the URB_SHORT_NOT_OK
83	flag is set.  Completion handlers for isochronous URBs should only see
84	urb->status set to zero, -ENOENT, -ECONNRESET, -ESHUTDOWN, or -EREMOTEIO.
85	Individual frame descriptor status fields may report more status codes.
86	
87	
88	0			Transfer completed successfully
89	
90	-ENOENT			URB was synchronously unlinked by usb_unlink_urb
91	
92	-EINPROGRESS		URB still pending, no results yet
93				(That is, if drivers see this it's a bug.)
94	
95	-EPROTO (*, **)		a) bitstuff error
96				b) no response packet received within the
97				   prescribed bus turn-around time
98				c) unknown USB error 
99	
100	-EILSEQ (*, **)		a) CRC mismatch
101				b) no response packet received within the
102				   prescribed bus turn-around time
103				c) unknown USB error 
104	
105				Note that often the controller hardware does not
106				distinguish among cases a), b), and c), so a
107				driver cannot tell whether there was a protocol
108				error, a failure to respond (often caused by
109				device disconnect), or some other fault.
110	
111	-ETIME (**)		No response packet received within the prescribed
112				bus turn-around time.  This error may instead be
113				reported as -EPROTO or -EILSEQ.
114	
115	-ETIMEDOUT		Synchronous USB message functions use this code
116				to indicate timeout expired before the transfer
117				completed, and no other error was reported by HC.
118	
119	-EPIPE (**)		Endpoint stalled.  For non-control endpoints,
120				reset this status with usb_clear_halt().
121	
122	-ECOMM			During an IN transfer, the host controller
123				received data from an endpoint faster than it
124				could be written to system memory
125	
126	-ENOSR			During an OUT transfer, the host controller
127				could not retrieve data from system memory fast
128				enough to keep up with the USB data rate
129	
130	-EOVERFLOW (*)		The amount of data returned by the endpoint was
131				greater than either the max packet size of the
132				endpoint or the remaining buffer size.  "Babble".
133	
134	-EREMOTEIO		The data read from the endpoint did not fill the
135				specified buffer, and URB_SHORT_NOT_OK was set in
136				urb->transfer_flags.
137	
138	-ENODEV			Device was removed.  Often preceded by a burst of
139				other errors, since the hub driver doesn't detect
140				device removal events immediately.
141	
142	-EXDEV			ISO transfer only partially completed
143				(only set in iso_frame_desc[n].status, not urb->status)
144	
145	-EINVAL			ISO madness, if this happens: Log off and go home
146	
147	-ECONNRESET		URB was asynchronously unlinked by usb_unlink_urb
148	
149	-ESHUTDOWN		The device or host controller has been disabled due
150				to some problem that could not be worked around,
151				such as a physical disconnect.
152	
153	
154	(*) Error codes like -EPROTO, -EILSEQ and -EOVERFLOW normally indicate
155	hardware problems such as bad devices (including firmware) or cables.
156	
157	(**) This is also one of several codes that different kinds of host
158	controller use to indicate a transfer has failed because of device
159	disconnect.  In the interval before the hub driver starts disconnect
160	processing, devices may receive such fault reports for every request.
161	
162	
163	
164	**************************************************************************
165	*              Error codes returned by usbcore-functions                 *
166	*           (expect also other submit and transfer status codes)         *
167	**************************************************************************
168	
169	usb_register():
170	-EINVAL			error during registering new driver
171	
172	usb_get_*/usb_set_*():
173	usb_control_msg():
174	usb_bulk_msg():
175	-ETIMEDOUT		Timeout expired before the transfer completed.
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