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-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
  72USB device drivers may only test urb status values in completion handlers.
  73This is because otherwise there would be a race between HCDs updating
  74these values on one CPU, and device drivers testing them on another CPU.
  75
  76A transfer's actual_length may be positive even when an error has been
  77reported.  That's because transfers often involve several packets, so that
  78one or more packets could finish before an error stops further endpoint I/O.
  79
  80For isochronous URBs, the urb status value is non-zero only if the URB is
  81unlinked, the device is removed, the host controller is disabled, or the total
  82transferred length is less than the requested length and the URB_SHORT_NOT_OK
  83flag is set.  Completion handlers for isochronous URBs should only see
  84urb->status set to zero, -ENOENT, -ECONNRESET, -ESHUTDOWN, or -EREMOTEIO.
  85Individual frame descriptor status fields may report more status codes.
  86
  87
  880                       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
 155hardware problems such as bad devices (including firmware) or cables.
 156
 157(**) This is also one of several codes that different kinds of host
 158controller use to indicate a transfer has failed because of device
 159disconnect.  In the interval before the hub driver starts disconnect
 160processing, 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
 169usb_register():
 170-EINVAL                 error during registering new driver
 171
 172usb_get_*/usb_set_*():
 173usb_control_msg():
 174usb_bulk_msg():
 175-ETIMEDOUT              Timeout expired before the transfer completed.
 176
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