On Tue, 26 Mar 2013, victor yeo wrote: > Understand, UDC driver will call driver->setup(), and if the return > value is negative, UDC driver has to set dev->protocol_stall = 1 and > maybe call usb_ep_set_halt(). However, the hardware won't be able to > send out zero length response. Don't be silly; of course it can. Nobody would be foolish enough to design a piece of USB hardware that couldn't send a zero-length DATA packet. > I think the purpose of zero length > response is to get an ACK from the host. The purpose of the zero-length response is to complete the Status stage of a control-OUT transfer. 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
