Re: A QUESTION ABOUT USB DRIVER

[Oliver Neukum]

Am Montag, 11. Januar 2010 06:14:31 schrieb Steven Xu:
> output: usb 1-1: device descriptor read/64, error -71
> 
> 
> in drivers/usb/core/hub.c  line 2250
> when a udisk inserted run to here
>                         for (j = 0; j < 3; ++j) {
>                                 buf->bMaxPacketSize0 = 0;
> 
>                                 r = usb_control_msg(udev, usb_rcvaddr0pipe(),
>                                         USB_REQ_GET_DESCRIPTOR, USB_DIR_IN,
>                                         USB_DT_DEVICE << 8, 0,
>                                         buf, GET_DESCRIPTOR_BUFSIZE,
>                                         (i ? USB_CTRL_GET_TIMEOUT : 1000));
>  return r=-74,
> 
> WHAT IS THE POSSIBEL REASON FOR THIS?
> THANKS!

This is -EPROTO. It means that a low level error on the wire happened,
for example a device sent a malformed package. This is a very unspecific
error.

	HTH
		Oliver
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