On Wed, 9 May 2012, Sarah Sharp wrote: > > Anyway, I just checked the xHCI spec. As far as I can see, it doesn't > > directly require that a transfer TRB's completion code be set to Short > > Packet when the ISP flag isn't set. So it may be a mistake to rely on > > that -- presumably you don't set ISP for ischronous transfers. > > The xHCI driver does set ISP for all TRBs for an isochronous IN > endpoint, see drivers/usb/host/xhci-ring.c:xhci_queue_isoc_tx() > > /* Only set interrupt on short packet for IN EPs */ > if (usb_urb_dir_in(urb)) > field |= TRB_ISP; > > Otherwise we won't get an event when a short packet occurs. Since we > set ISP on all isoc TRBs, the host should have set the completion code > to Short Packet. Okay. Why do you care about short packets on isochronous transfers? I wouldn't think they make any difference. > Basically, I still think the Fresco Logic host is broken. :) Sounds like it. 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
