On Wed, 29 Jun 2011, Kirill Smelkov wrote: > > Also, when decreasing the schedule limit, do you think it is really > > necessary to check that the current allocation doesn't exceed the new > > limit? I think it would be sufficient to apply the new limit just to > > new bandwidth allocation requests. After all, this API is meant for > > experts only. > > I think yes, it is needed. E.g. because there is this check in > periodic_usecs(): > > #ifdef DEBUG > if (usecs > ehci->uframe_periodic_max) > ehci_err (ehci, "uframe %d sched overrun: %d usecs\n", > frame * 8 + uframe, usecs); > #endif > return usecs; > } > > and periodic_usecs() is called in e.g. this chain: > > itd_submit > iso_stream_schedule > itd_slot_ok > periodic_usecs > > and others. That won't matter unless DEBUG is defined. > I'd leave this check as is - to me it would be useful in debug mode to > verify that we've not overallocated a period. > > Also, even if this knob would be useful only to experts, it would be > better to put feedback onto the knob so that people could know whether > thir request could be served or not. > > What do you think? Can you make that check conditional on DEBUG being set? 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
