3 This is the documentation of (hopefully) all possible error codes (and
4 their interpretation) that can be returned from usbcore.
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.
12 **************************************************************************
13 * Error codes returned by usb_submit_urb *
14 **************************************************************************
18 0 URB submission went fine
20 -ENOMEM no memory for allocation of internal structures
24 -ENODEV specified USB-device or bus doesn't exist
26 -ENOENT specified interface or endpoint does not exist or
29 -ENXIO host controller driver does not support queuing of this type
30 of urb. (treat as a host controller bug.)
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
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.
42 -EFBIG Host controller driver can't schedule that many ISO frames.
44 -EPIPE The pipe type specified in the URB doesn't match the
45 endpoint's actual type.
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.
53 -ENOSPC This request would overcommit the usb bandwidth reserved
54 for periodic transfers (interrupt, isochronous).
56 -ESHUTDOWN The device or host controller has been disabled due to some
57 problem that could not be worked around.
59 -EPERM Submission failed because urb->reject was set.
61 -EHOSTUNREACH URB was rejected because the device is suspended.
63 -ENOEXEC A control URB doesn't contain a Setup packet.
66 **************************************************************************
67 * Error codes returned by in urb->status *
68 * or in iso_frame_desc[n].status (for ISO) *
69 **************************************************************************
71 USB device drivers may only test urb status values in completion handlers.
72 This is because otherwise there would be a race between HCDs updating
73 these values on one CPU, and device drivers testing them on another CPU.
75 A transfer's actual_length may be positive even when an error has been
76 reported. That's because transfers often involve several packets, so that
77 one or more packets could finish before an error stops further endpoint I/O.
79 For isochronous URBs, the urb status value is non-zero only if the URB is
80 unlinked, the device is removed, the host controller is disabled, or the total
81 transferred length is less than the requested length and the URB_SHORT_NOT_OK
82 flag is set. Completion handlers for isochronous URBs should only see
83 urb->status set to zero, -ENOENT, -ECONNRESET, -ESHUTDOWN, or -EREMOTEIO.
84 Individual frame descriptor status fields may report more status codes.
87 0 Transfer completed successfully
89 -ENOENT URB was synchronously unlinked by usb_unlink_urb
91 -EINPROGRESS URB still pending, no results yet
92 (That is, if drivers see this it's a bug.)
94 -EPROTO (*, **) a) bitstuff error
95 b) no response packet received within the
96 prescribed bus turn-around time
99 -EILSEQ (*, **) a) CRC mismatch
100 b) no response packet received within the
101 prescribed bus turn-around time
104 Note that often the controller hardware does not
105 distinguish among cases a), b), and c), so a
106 driver cannot tell whether there was a protocol
107 error, a failure to respond (often caused by
108 device disconnect), or some other fault.
110 -ETIME (**) No response packet received within the prescribed
111 bus turn-around time. This error may instead be
112 reported as -EPROTO or -EILSEQ.
114 -ETIMEDOUT Synchronous USB message functions use this code
115 to indicate timeout expired before the transfer
116 completed, and no other error was reported by HC.
118 -EPIPE (**) Endpoint stalled. For non-control endpoints,
119 reset this status with usb_clear_halt().
121 -ECOMM During an IN transfer, the host controller
122 received data from an endpoint faster than it
123 could be written to system memory
125 -ENOSR During an OUT transfer, the host controller
126 could not retrieve data from system memory fast
127 enough to keep up with the USB data rate
129 -EOVERFLOW (*) The amount of data returned by the endpoint was
130 greater than either the max packet size of the
131 endpoint or the remaining buffer size. "Babble".
133 -EREMOTEIO The data read from the endpoint did not fill the
134 specified buffer, and URB_SHORT_NOT_OK was set in
137 -ENODEV Device was removed. Often preceded by a burst of
138 other errors, since the hub driver doesn't detect
139 device removal events immediately.
141 -EXDEV ISO transfer only partially completed
142 (only set in iso_frame_desc[n].status, not urb->status)
144 -EINVAL ISO madness, if this happens: Log off and go home
146 -ECONNRESET URB was asynchronously unlinked by usb_unlink_urb
148 -ESHUTDOWN The device or host controller has been disabled due
149 to some problem that could not be worked around,
150 such as a physical disconnect.
153 (*) Error codes like -EPROTO, -EILSEQ and -EOVERFLOW normally indicate
154 hardware problems such as bad devices (including firmware) or cables.
156 (**) This is also one of several codes that different kinds of host
157 controller use to indicate a transfer has failed because of device
158 disconnect. In the interval before the hub driver starts disconnect
159 processing, devices may receive such fault reports for every request.
163 **************************************************************************
164 * Error codes returned by usbcore-functions *
165 * (expect also other submit and transfer status codes) *
166 **************************************************************************
169 -EINVAL error during registering new driver
171 usb_get_*/usb_set_*():
174 -ETIMEDOUT Timeout expired before the transfer completed.