1 files changed, 29 insertions, 0 deletions

diff --git a/usbmuxd/usb-linux.c b/usbmuxd/usb-linux.c
index fb22d03..2d6053e 100644
--- a/usbmuxd/usb-linux.c
+++ b/usbmuxd/usb-linux.c
@@ -33,6 +33,17 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 #include "log.h"
 #include "device.h"
 
+#ifndef LIBUSB_TRANSFER_ZERO_PACKET
+#warning Your libusb is missing proper Zero Length Packet support!
+#warning
+#warning If you are using a recent libusb Git, things may or may not work.
+#warning If you are using libusb 1.0.2 or earlier, things will definitely not work
+#warning properly.
+#warning
+#warning Please apply the patch in the contrib/ directory to your libusb 1.0 tree.
+#define EXPLICIT_ZLP_TRANSACTION
+#endif
+
 // interval for device connection/disconnection polling, in milliseconds
 // we need this because there is currently no asynchronous device discovery mechanism in libusb
 #define DEVICE_POLL_TIME 1000
@@ -134,15 +145,33 @@ int usb_send(struct usb_device *dev, const unsigned char *buf, int length)
         struct libusb_transfer *xfer = libusb_alloc_transfer(0);
         libusb_fill_bulk_transfer(xfer, dev->dev, BULK_OUT, (void*)buf, length, tx_callback, dev, 0);
         xfer->flags = LIBUSB_TRANSFER_SHORT_NOT_OK;
+#ifndef EXPLICIT_ZLP_TRANSACTION
         if (length % dev->wMaxPacketSize == 0) {
                 xfer->flags |= LIBUSB_TRANSFER_ZERO_PACKET;
         }
+#endif
         if((res = libusb_submit_transfer(xfer)) < 0) {
                 usbmuxd_log(LL_ERROR, "Failed to submit TX transfer %p len %d to device %d-%d: %d", buf, length, dev->bus, dev->address, res);
                 libusb_free_transfer(xfer);
                 return res;
         }
         collection_add(&dev->tx_xfers, xfer);
+#ifdef EXPLICIT_ZLP_TRANSACTION
+        if (length % dev->wMaxPacketSize == 0) {
+                usbmuxd_log(LL_DEBUG, "Send ZLP");
+                // Send Zero Length Packet
+                xfer = libusb_alloc_transfer(0);
+                void *buffer = malloc(1);
+                libusb_fill_bulk_transfer(xfer, dev->dev, BULK_OUT, buffer, 0, tx_callback, dev, 0);
+                xfer->flags = LIBUSB_TRANSFER_SHORT_NOT_OK;
+                if((res = libusb_submit_transfer(xfer)) < 0) {
+                        usbmuxd_log(LL_ERROR, "Failed to submit TX ZLP transfer to device %d-%d: %d", dev->bus, dev->address, res);
+                        libusb_free_transfer(xfer);
+                        return res;
+                }
+                collection_add(&dev->tx_xfers, xfer);
+        }
+#endif
         return 0;
 }