Comment 36 for bug 88746

Revision history for this message
Mika Kukkonen (mikukkon) wrote : Re: [Bug 88746] Re: USB devices are not recognized when having ehci_hcd modprobed

I dug into kernel code a bit, and looked where does the
/var/log/kern.log messages come (at least in my case):

usb 3-2: new high speed USB device using ehci_hcd and address 11
usb 3-2: device descriptor read/64, error -71
usb 3-2: device descriptor read/64, error -71

As far I as I can read the code, that -71 is EPROTO and it gets set by
the following
code in usb_get_descriptor() in file drivers/usb/core/message.c :

  result = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
    USB_REQ_GET_DESCRIPTOR, USB_DIR_IN,
    (type << 8) + index, 0, buf, size,
    USB_CTRL_GET_TIMEOUT);
  if (result == 0 || result == -EPIPE)
   continue;
  if (result > 1 && ((u8 *)buf)[1] != type) {
   result = -EPROTO;
   continue;
  }

Not much help there. Do others have the same error code/message in
their kern.log?