On Wed, 29 Aug 2012, Sebastian Andrzej Siewior wrote: > > > The BULK URBs usually don't make a scene. They re-submit the complete > > > queue length in BH so we have a little time in between. The INTR URB is > > > more evil because usbnet's intr_complete() causes to re-submitt it > > > immediately. That means we hardly do any progress and end up in a > > > busy loop. > > > > This sounds like a possible bug in usbnet. If usbnet encounters > > repeated failures while trying to communicate with a USB device, it > > shouldn't continue to retry indefinitely. It should eventually give > > up, and maybe do a device reset. > > So to interrupt the intr packets we need atleast > > diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c > index 8531c1c..8dc3705 100644 > --- a/drivers/net/usb/usbnet.c > +++ b/drivers/net/usb/usbnet.c > @@ -194,6 +194,7 @@ static void intr_complete (struct urb *urb) > /* software-driven interface shutdown */ > case -ENOENT: /* urb killed */ > case -ESHUTDOWN: /* hardware gone */ > + case -EPIPE: > netif_dbg(dev, ifdown, dev->net, > "intr shutdown, code %d\n", status); > return; No, that's not right. For one thing, the error is -EPROTO, not -EPIPE. But aside from that, usbnet has a comment a little farther down: /* NOTE: not throttling like RX/TX, since this endpoint * already polls infrequently */ Corresponding to this, there's a comment in dummy-hcd: case PIPE_INTERRUPT: /* FIXME is it urb->interval since the last xfer? * this almost certainly polls too fast. */ So the problem appears to be that dummy-hcd doesn't implement the right interval for periodic transfers. I'd accept a patch to fix that. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
