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 -EXDEV ISO: URB_ISO_ASAP wasn't specified and all the frames
39 the URB would be scheduled in have already expired.
41 -EFBIG Host controller driver can't schedule that many ISO frames.
43 -EPIPE The pipe type specified in the URB doesn't match the
44 endpoint's actual type.
46 -EMSGSIZE (a) endpoint maxpacket size is zero; it is not usable
47 in the current interface altsetting.
48 (b) ISO packet is larger than the endpoint maxpacket.
49 (c) requested data transfer length is invalid: negative
50 or too large for the host controller.
52 -ENOSPC This request would overcommit the usb bandwidth reserved
53 for periodic transfers (interrupt, isochronous).
55 -ESHUTDOWN The device or host controller has been disabled due to some
56 problem that could not be worked around.
58 -EPERM Submission failed because urb->reject was set.
60 -EHOSTUNREACH URB was rejected because the device is suspended.
62 -ENOEXEC A control URB doesn't contain a Setup packet.
65 **************************************************************************
66 * Error codes returned by in urb->status *
67 * or in iso_frame_desc[n].status (for ISO) *
68 **************************************************************************
70 USB device drivers may only test urb status values in completion handlers.
71 This is because otherwise there would be a race between HCDs updating
72 these values on one CPU, and device drivers testing them on another CPU.
74 A transfer's actual_length may be positive even when an error has been
75 reported. That's because transfers often involve several packets, so that
76 one or more packets could finish before an error stops further endpoint I/O.
78 For isochronous URBs, the urb status value is non-zero only if the URB is
79 unlinked, the device is removed, the host controller is disabled, or the total
80 transferred length is less than the requested length and the URB_SHORT_NOT_OK
81 flag is set. Completion handlers for isochronous URBs should only see
82 urb->status set to zero, -ENOENT, -ECONNRESET, -ESHUTDOWN, or -EREMOTEIO.
83 Individual frame descriptor status fields may report more status codes.
86 0 Transfer completed successfully
88 -ENOENT URB was synchronously unlinked by usb_unlink_urb
90 -EINPROGRESS URB still pending, no results yet
91 (That is, if drivers see this it's a bug.)
93 -EPROTO (*, **) a) bitstuff error
94 b) no response packet received within the
95 prescribed bus turn-around time
98 -EILSEQ (*, **) a) CRC mismatch
99 b) no response packet received within the
100 prescribed bus turn-around time
103 Note that often the controller hardware does not
104 distinguish among cases a), b), and c), so a
105 driver cannot tell whether there was a protocol
106 error, a failure to respond (often caused by
107 device disconnect), or some other fault.
109 -ETIME (**) No response packet received within the prescribed
110 bus turn-around time. This error may instead be
111 reported as -EPROTO or -EILSEQ.
113 -ETIMEDOUT Synchronous USB message functions use this code
114 to indicate timeout expired before the transfer
115 completed, and no other error was reported by HC.
117 -EPIPE (**) Endpoint stalled. For non-control endpoints,
118 reset this status with usb_clear_halt().
120 -ECOMM During an IN transfer, the host controller
121 received data from an endpoint faster than it
122 could be written to system memory
124 -ENOSR During an OUT transfer, the host controller
125 could not retrieve data from system memory fast
126 enough to keep up with the USB data rate
128 -EOVERFLOW (*) The amount of data returned by the endpoint was
129 greater than either the max packet size of the
130 endpoint or the remaining buffer size. "Babble".
132 -EREMOTEIO The data read from the endpoint did not fill the
133 specified buffer, and URB_SHORT_NOT_OK was set in
136 -ENODEV Device was removed. Often preceded by a burst of
137 other errors, since the hub driver doesn't detect
138 device removal events immediately.
140 -EXDEV ISO transfer only partially completed
141 (only set in iso_frame_desc[n].status, not urb->status)
143 -EINVAL ISO madness, if this happens: Log off and go home
145 -ECONNRESET URB was asynchronously unlinked by usb_unlink_urb
147 -ESHUTDOWN The device or host controller has been disabled due
148 to some problem that could not be worked around,
149 such as a physical disconnect.
152 (*) Error codes like -EPROTO, -EILSEQ and -EOVERFLOW normally indicate
153 hardware problems such as bad devices (including firmware) or cables.
155 (**) This is also one of several codes that different kinds of host
156 controller use to indicate a transfer has failed because of device
157 disconnect. In the interval before the hub driver starts disconnect
158 processing, devices may receive such fault reports for every request.
162 **************************************************************************
163 * Error codes returned by usbcore-functions *
164 * (expect also other submit and transfer status codes) *
165 **************************************************************************
168 -EINVAL error during registering new driver
170 usb_get_*/usb_set_*():
173 -ETIMEDOUT Timeout expired before the transfer completed.