func: static int xhci_submit(XHCIState *xhci, XHCITransfer *xfer, XHCIEPContext *epctx) xfer -> in_xfer = epctx -> type >> 2; switch ( epctx -> type )  xfer -> pkts = 0; xfer -> iso_xfer = false; xfer -> timed_xfer = true; if ( xfer -> running_retry )  xfer -> pkts = 0; xfer -> iso_xfer = false; xfer -> timed_xfer = false; xfer -> pkts = 1; xfer -> iso_xfer = true; xfer -> timed_xfer = true; if ( xfer -> running_retry )  if ( xhci_setup_packet ( xfer ) < 0 )  if ( ! xfer -> running_async && ! xfer -> running_retry )  xhci_kick_ep ( xhci , xfer -> slotid , xfer -> epid , xfer -> streamid ); static void xhci_kick_ep(XHCIState *xhci, unsigned int unsigned int epid, unsigned int streamid) XHCIEPContext * epctx ; if ( ! xhci -> slots [ slotid - 1 ] . enabled )  epctx = xhci -> slots [ slotid - 1 ] . eps [ epid - 1 ]; if ( ! epctx )  if ( ! xhci -> slots [ slotid - 1 ] . uport || ! xhci -> slots [ slotid - 1 ] . uport -> dev || ! xhci -> slots [ slotid - 1 ] . uport -> dev -> attached )  if ( epctx -> retry )  XHCITransfer * xfer = epctx -> retry ; if ( xfer -> timed_xfer )  if ( xfer -> running_retry )  xfer -> timed_xfer = 0; xfer -> running_retry = 1; if ( xfer -> iso_xfer )  if ( xhci_setup_packet ( xfer ) < 0 )  if ( xhci_setup_packet ( xfer ) < 0 )  if ( xfer -> packet . status == USB_RET_NAK )  epctx -> retry = NULL; if ( epctx -> state == EP_HALTED )  if ( epctx -> nr_pstreams )  xhci_set_ep_state ( xhci , epctx , NULL , EP_RUNNING ); static void xhci_set_ep_state(XHCIState *xhci, XHCIEPContext XHCIStreamContext *sctx, uint32_t state) uint32_t ctx [ 5 ] ; xhci_dma_read_u32s ( xhci , epctx -> pctx , ctx , sizeof ( ctx ) ); static inline void xhci_dma_read_u32s(XHCIState *xhci, dma_addr_t uint32_t *buf, size_t len) assert ( ( len % sizeof ( uint32_t ) ) == 0 ); 