On Tuesday 10 October 2006 12:26 pm, Alan Stern wrote: > > You're talking about detecting URB completion before a completion IRQ > arrives. In other words, polling. I would prefer not to see that added > to the HCDs, but it is a possibility.
Actually EHCI can and does run into a similar case, because the way it detects transfer completion is by scanning the schedule ... that can be done at any time, even without an IRQ. EHCI could run in a purely polled mode, and the IRQ just another "please poll" request. OHCI on the other hand must rely on the "donelist", even for TDs it can see are marked "done". So it's got to rely on at least IRQ status if not actual IRQs, since taking the donelist contents away from the controller before the IRQ status is reported is very racey. > The packet transfer may occur anywhere during the frame; the device would > not be able to count on the data being available in time to play when the > frame begins. Right. - Dave ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
