On Wed, 2 May 2007, [UTF-8] Alex VillacÃÂs Lasso wrote: > >> submit the interrupt urbs for either endpoint in the driver code, my > >> callback > >> code never gets called at all - not even to signal an error while > >> submitting the > >> urb. > >> > > > > That never happens. The callback routine is invoked when the URB > > completes, and if the submission failed then the URB wasn't accepted so of > > course it can never complete. > > > > > Hmm... I was under the impression that if usb_submit_urb() returned 0, > then the callback routine would eventually get called, either because it > completed,
That much is right. > or because an error occurred in submission - such as a timeout. No. If usb_submit_urb() returned 0 then by definition an error did not occur in submission. A timeout isn't a submission error, and in fact the URB-handling parts of the USB stack don't have any timeouts. > > Apparently your driver doesn't send anything to the device when it is > > probed. > > > > > The stir4200 driver also doesn't do anything to the device, other than > usb_reset_configuration(). What kind of operation might be necessary to > do at the probe function? How should I know? It depends entirely on the device. On the other hand, I doubt that the usb_reset_configuration() call is needed. It merely duplicates what the USB core did a few moments earlier. > > Why does your driver bother to do a Clear-Halt? It should not be needed. > > > > > Again, because stir4200 does it and I was taking it as one of the models > for writing my driver. I thought this was a required part of the setup. > I will try removing it at home and see if it makes any difference. It almost certainly is not required. > > Like Oliver said, you probably need to do some sort of initialization of > > the device before it will start working. > > > > Alan Stern > > > > > Maybe, but I could not find any evidence of such an initialization > sequence in the SnoopyPro dump done under Windows XP (attached). I > deduced that no initialization sequence was needed. So, I am not looking > hard enough, or SnoopyPro is buggy / hides information from me. I don't see anything special in the log either. Maybe the device simply doesn't like your Clear-Halt requests. Alan Stern ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
