linux/Documentation/usb/error-codes.txt
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   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
  79For isochronous URBs, the urb status value is non-zero only if the URB is
  80unlinked, the device is removed, the host controller is disabled, or the total
  81transferred length is less than the requested length and the URB_SHORT_NOT_OK
  82flag is set.  Completion handlers for isochronous URBs should only see
  83urb->status set to zero, -ENOENT, -ECONNRESET, -ESHUTDOWN, or -EREMOTEIO.
  84Individual frame descriptor status fields may report more status codes.
  85
  86
  870                       Transfer completed successfully
  88
  89-ENOENT                 URB was synchronously unlinked by usb_unlink_urb
  90
  91-EINPROGRESS            URB still pending, no results yet
  92                        (That is, if drivers see this it's a bug.)
  93
  94-EPROTO (*, **)         a) bitstuff error
  95                        b) no response packet received within the
  96                           prescribed bus turn-around time
  97                        c) unknown USB error 
  98
  99-EILSEQ (*, **)         a) CRC mismatch
 100                        b) no response packet received within the
 101                           prescribed bus turn-around time
 102                        c) unknown USB error 
 103
 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.
 109
 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.
 113
 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.
 117
 118-EPIPE (**)             Endpoint stalled.  For non-control endpoints,
 119                        reset this status with usb_clear_halt().
 120
 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
 124
 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
 128
 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".
 132
 133-EREMOTEIO              The data read from the endpoint did not fill the
 134                        specified buffer, and URB_SHORT_NOT_OK was set in
 135                        urb->transfer_flags.
 136
 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.
 140
 141-EXDEV                  ISO transfer only partially completed
 142                        (only set in iso_frame_desc[n].status, not urb->status)
 143
 144-EINVAL                 ISO madness, if this happens: Log off and go home
 145
 146-ECONNRESET             URB was asynchronously unlinked by usb_unlink_urb
 147
 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.
 151
 152
 153(*) Error codes like -EPROTO, -EILSEQ and -EOVERFLOW normally indicate
 154hardware problems such as bad devices (including firmware) or cables.
 155
 156(**) This is also one of several codes that different kinds of host
 157controller use to indicate a transfer has failed because of device
 158disconnect.  In the interval before the hub driver starts disconnect
 159processing, devices may receive such fault reports for every request.
 160
 161
 162
 163**************************************************************************
 164*              Error codes returned by usbcore-functions                 *
 165*           (expect also other submit and transfer status codes)         *
 166**************************************************************************
 167
 168usb_register():
 169-EINVAL                 error during registering new driver
 170
 171usb_get_*/usb_set_*():
 172usb_control_msg():
 173usb_bulk_msg():
 174-ETIMEDOUT              Timeout expired before the transfer completed.
 175
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