On Friday 18 February 2005 3:03 am, Thibaut VARENE wrote:
> Hi again
>
> On rare occasions, error -71 (-EPROTO) shows up for the same endpoint
> (ie: the only thing that changes in the logmessage is the error
> value), which seems coherent with the timeout issue ("-EPROTO:
> bitstuff error during the transfer or No response packet was received
> in time by the hardware").
If you're using OHCI, you know that EPROTO reflects a real protocol
error from the device -- never a timeout.
> What are the likely causes of such a behaviour?
OHCI returns that error on a bitstuffing error, or when the wrong
PID comes back. So basically the signal written by the BT adapter
looked bogus when it arrived at the USB host.
> Is it possible that this symptom is the consequence of a bug in the
> HCI USB layer, and not an actual OHCI bug?
I could imagine that. You might be able to recover by having
some task issue a CLEAR_HALT request to that endpoint (using
the standard USB API) and continuing.
> Could it be a hardware bug?
Yes.
- Dave
> FWIW, when the timeout happens, the stack looks like this:
>
> hci_usb_rx_complete
> usb_hcd_giveback_urb
> finish_urb
> dl_done_list
> ohci_irq
> usb_hcd_irq
> __do_irq
-------------------------------------------------------
SF email is sponsored by - The IT Product Guide
Read honest & candid reviews on hundreds of IT Products from real users.
Discover which products truly live up to the hype. Start reading now.
http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click
_______________________________________________
linux-usb-devel@lists.sourceforge.net
To unsubscribe, use the last form field at:
https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
