Root/Documentation/usb/error-codes.txt

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

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