On Thu, 23 Jun 2011, Kirill Smelkov wrote: > > At 480 Mb/s, each microframe holds 7500 bytes (less if you count > > bit-stuffing). 4% of that is 300 bytes, which is not enough for a > > 512-byte bulk packet. I think you'd run into trouble trying to do any > > serious bulk transfers on such a tight schedule. > > Yes, you seem to be right. > > I still think 4% is maybe enough for control traffic. It should be. > > > @@ -571,6 +579,14 @@ static int ehci_init(struct usb_hcd *hcd) > > > hcc_params = ehci_readl(ehci, &ehci->caps->hcc_params); > > > > > > /* > > > + * tell user, if using non-standard (80% == 100 usec/uframe) bandwidth > > > + */ > > > + if (uframe_periodic_max != 100) > > > + ehci_info(ehci, "using non-standard max periodic bandwith " > > > + "(%u%% == %u usec/uframe)", > > > + 100*uframe_periodic_max/125, uframe_periodic_max); > > > + > > > + /* > > > > Check for invalid values. This should never be less than 100 or > > greater than 125. > > Ok. By the way, why should we limit it to be not less than 100? > Likewise, a user who knows exactly what he/she is doing could limit > periodic bandwidth to be less than 80% required by USB specification. What's the point? If you want to use less than 80% of your bandwidth for periodic transfers, go ahead and do so. You don't need to change the limit. 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
