If sent packet size is wMaxPacketSize boundary, this device doesn't answer. To fix this, we have to send zero-length packet in usb spec. Signed-off-by: OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx> --- drivers/nfc/port100.c | 1 + 1 file changed, 1 insertion(+) diff -puN drivers/nfc/port100.c~nfc-need-zero-packet drivers/nfc/port100.c --- linux-ibmpc/drivers/nfc/port100.c~nfc-need-zero-packet 2016-12-31 18:27:14.814753508 +0900 +++ linux-ibmpc-hirofumi/drivers/nfc/port100.c 2016-12-31 18:32:12.928334607 +0900 @@ -1540,6 +1540,7 @@ static int port100_probe(struct usb_inte usb_fill_bulk_urb(dev->out_urb, dev->udev, usb_sndbulkpipe(dev->udev, out_endpoint), NULL, 0, port100_send_complete, dev); + dev->out_urb->transfer_flags = URB_ZERO_PACKET; dev->skb_headroom = PORT100_FRAME_HEADER_LEN + PORT100_COMM_RF_HEAD_MAX_LEN; _ -- OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx>