On Mon, 2 Nov 2015, Peter Chen wrote: > Hi Alan, > > After a discussion with IC engineer, a brief idea like below: > > - Delete the QH from the asynclist directly, Issue the first IAA > routine, this is we do now. > - During the first IAA interrupt, judge if asynclistaddr is next address of > the QH we want to remove, if it does not, issue the second IAA > routine, else, we consider the controller will not process the removed > QH any more, so it is safe to remove. > - If the controller still handles the QH previous than the one we want to > remove , issue IAA again. I don't understand this completely. It sounds like you're saying: Find qh2 such that qh2->qh_next == &qh. Keep doing IAA interrupts until (asynclistaddr != qh2->qh_dma && asynclistaddr != qh->qh_dma). Is that what you mean? It doesn't sound right. Consider the case where the async list contains only two QHs: qh2 and qh. Then asynclistaddr will always point to one or the other. What about this instead? Keep doing IAA interrupts until (asynclistaddr != qh->qh_dma). Then do one more IAA interrupt. That seems safer. 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
