On Tue, 3 Dec 2013, yoma sophian wrote: > > This isn't a race condition, because the driver does not terminate > > isochronous URBs before they are scheduled to end. > > > > For example, suppose there was an isochronous URB that was scheduled to > > transmit packets during microframes 100, 180, 260, and 340. If an > > interrupt for a bulk URB happens during microframe 212, the driver will > > not terminate the isochronous URB, because it is not scheduled to end > > yet. But if an interrupt for a bulk URB happens during microframe 347, > > then the driver will terminate the isochronous URB, because that is > > after the scheduled end (which is microframe 340). > how about situation like below: > HW Frame index is located at microframe 90. And there was an > isochronous URB that was scheduled to transmit packets during > microframes 100, 180, 260, and 340. > > Interrupt happen for Bulk when HW increase Frame index to 98. > > After driver scan asynchronous schedule, driver finds > ehci->isoc_count != 0 and start scan_isoc. > Isn't it possible that Driver may drop those previous scheduled > isochronous packets? No, it's not possible. The packets won't be removed from the schedule until after microframe 340. 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
