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Diffstat (limited to 'Documentation/usb/error-codes.txt')
| -rw-r--r-- | Documentation/usb/error-codes.txt | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/Documentation/usb/error-codes.txt b/Documentation/usb/error-codes.txt new file mode 100644 index 00000000000..1e36f1661cd --- /dev/null +++ b/Documentation/usb/error-codes.txt @@ -0,0 +1,167 @@ +Revised: 2004-Oct-21 + +This is the documentation of (hopefully) all possible error codes (and +their interpretation) that can be returned from usbcore. + +Some of them are returned by the Host Controller Drivers (HCDs), which +device drivers only see through usbcore. As a rule, all the HCDs should +behave the same except for transfer speed dependent behaviors and the +way certain faults are reported. + + +************************************************************************** +* Error codes returned by usb_submit_urb * +************************************************************************** + +Non-USB-specific: + +0 URB submission went fine + +-ENOMEM no memory for allocation of internal structures + +USB-specific: + +-ENODEV specified USB-device or bus doesn't exist + +-ENOENT specified interface or endpoint does not exist or + is not enabled + +-ENXIO host controller driver does not support queuing of this type + of urb. (treat as a host controller bug.) + +-EINVAL a) Invalid transfer type specified (or not supported) + b) Invalid or unsupported periodic transfer interval + c) ISO: attempted to change transfer interval + d) ISO: number_of_packets is < 0 + e) various other cases + +-EAGAIN a) specified ISO start frame too early + b) (using ISO-ASAP) too much scheduled for the future + wait some time and try again. + +-EFBIG Host controller driver can't schedule that many ISO frames. + +-EPIPE Specified endpoint is stalled. For non-control endpoints, + reset this status with usb_clear_halt(). + +-EMSGSIZE (a) endpoint maxpacket size is zero; it is not usable + in the current interface altsetting. + (b) ISO packet is biger than endpoint maxpacket + (c) requested data transfer size is invalid (negative) + +-ENOSPC This request would overcommit the usb bandwidth reserved + for periodic transfers (interrupt, isochronous). + +-ESHUTDOWN The device or host controller has been disabled due to some + problem that could not be worked around. + +-EPERM Submission failed because urb->reject was set. + +-EHOSTUNREACH URB was rejected because the device is suspended. + + +************************************************************************** +* Error codes returned by in urb->status * +* or in iso_frame_desc[n].status (for ISO) * +************************************************************************** + +USB device drivers may only test urb status values in completion handlers. +This is because otherwise there would be a race between HCDs updating +these values on one CPU, and device drivers testing them on another CPU. + +A transfer's actual_length may be positive even when an error has been +reported. That's because transfers often involve several packets, so that +one or more packets could finish before an error stops further endpoint I/O. + + +0 Transfer completed successfully + +-ENOENT URB was synchronously unlinked by usb_unlink_urb + +-EINPROGRESS URB still pending, no results yet + (That is, if drivers see this it's a bug.) + +-EPROTO (*, **) a) bitstuff error + b) no response packet received within the + prescribed bus turn-around time + c) unknown USB error + +-EILSEQ (*, **) a) CRC mismatch + b) no response packet received within the + prescribed bus turn-around time + c) unknown USB error + + Note that often the controller hardware does not + distinguish among cases a), b), and c), so a + driver cannot tell whether there was a protocol + error, a failure to respond (often caused by + device disconnect), or some other fault. + +-ETIMEDOUT (**) No response packet received within the prescribed + bus turn-around time. This error may instead be + reported as -EPROTO or -EILSEQ. + + Note that the synchronous USB message functions + also use this code to indicate timeout expired + before the transfer completed. + +-EPIPE (**) Endpoint stalled. For non-control endpoints, + reset this status with usb_clear_halt(). + +-ECOMM During an IN transfer, the host controller + received data from an endpoint faster than it + could be written to system memory + +-ENOSR During an OUT transfer, the host controller + could not retrieve data from system memory fast + enough to keep up with the USB data rate + +-EOVERFLOW (*) The amount of data returned by the endpoint was + greater than either the max packet size of the + endpoint or the remaining buffer size. "Babble". + +-EREMOTEIO The data read from the endpoint did not fill the + specified buffer, and URB_SHORT_NOT_OK was set in + urb->transfer_flags. + +-ENODEV Device was removed. Often preceded by a burst of + other errors, since the hub driver does't detect + device removal events immediately. + +-EXDEV ISO transfer only partially completed + look at individual frame status for details + +-EINVAL ISO madness, if this happens: Log off and go home + +-ECONNRESET URB was asynchronously unlinked by usb_unlink_urb + +-ESHUTDOWN The device or host controller has been disabled due + to some problem that could not be worked around, + such as a physical disconnect. + + +(*) Error codes like -EPROTO, -EILSEQ and -EOVERFLOW normally indicate +hardware problems such as bad devices (including firmware) or cables. + +(**) This is also one of several codes that different kinds of host +controller use to to indicate a transfer has failed because of device +disconnect. In the interval before the hub driver starts disconnect +processing, devices may receive such fault reports for every request. + + + +************************************************************************** +* Error codes returned by usbcore-functions * +* (expect also other submit and transfer status codes) * +************************************************************************** + +usb_register(): +-EINVAL error during registering new driver + +usb_get_*/usb_set_*(): +usb_control_msg(): +usb_bulk_msg(): +-ETIMEDOUT Timeout expired before the transfer completed. + In the future this code may change to -ETIME, + whose definition is a closer match to this sort + of error. |