On Thu, 25 Jul 2013, Greg Kroah-Hartman wrote: > On Wed, Jul 03, 2013 at 10:53:09PM +0800, Ming Lei wrote: > > The patch does the below improvement: > > > > - think QH_STATE_COMPLETING as unlinking state since all URBs on the > > endpoint should be in unlinking or unlinked when doing endpoint_disable() > > > > - add "WARN_ON(!list_empty(&qh->qtd_list));" if qh->qh_state is > > QH_STATE_LINKED because there shouldn't be any active transfer in qh > > If this can "never" happen, why spit a nasty message out to the error > log? What can a user do with this? In this context, "never" means the only way it can happen is if there's a serious bug in the way usbcore handles altsetting and config changes. That code is sufficiently complicated that a little extra error checking won't hurt, IMO. If it ever happens, a user could post the log message on the mailing list, giving us a chance to find and fix the bug. > I really don't like adding stuff like this to the kernel if at all > possible. Up to you. Still, I think bringing situations like this to people's attention is a large part of what WARN_ON is intended for. 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
