1 files changed, 32 insertions, 1 deletions

diff --git a/src/usbmux.c b/src/usbmux.c
index 1d6497e..dd3ac1a 100644
--- a/src/usbmux.c
+++ b/src/usbmux.c
@@ -58,6 +58,7 @@ struct usbmux_device_int {
         struct usb_dev_handle *usbdev;
         struct usb_device *__device;
         receivebuf_t usbReceive;
+        int wMaxPacketSize;
 };
 
 typedef struct {
@@ -272,6 +273,24 @@ static int usbmux_config_usb_device(usbmux_device_t device)
                 log_debug_msg("done.\n");
         }
 
+        // get the last configuration
+        struct usb_config_descriptor *cfg = &device->__device->config[device->__device->descriptor.bNumConfigurations-1];
+        if (cfg && cfg->bNumInterfaces >= 2) {
+                struct usb_interface *ifp = &cfg->interface[1];
+                if (ifp && ifp->num_altsetting >= 1) {
+                        struct usb_interface_descriptor *as = &ifp->altsetting[0];
+                        int i;
+                        for (i = 0; i < as->bNumEndpoints; i++) {
+                                struct usb_endpoint_descriptor *ep=&as->endpoint[i];
+                                if (ep->bEndpointAddress == BULKOUT) {
+                                        device->wMaxPacketSize = ep->wMaxPacketSize;
+                                }
+                        }
+                }
+        }
+
+        log_debug_msg("Setting wMaxPacketSize to %d\n", device->wMaxPacketSize);
+
         do {
                 bytes = usb_bulk_read(device->usbdev, BULKIN, buf, 512, 800);
         } while (bytes > 0);
@@ -316,6 +335,9 @@ int usbmux_get_specific_device(int bus_n, int dev_n,
         newdevice->usbReceive.leftover = 0;
         newdevice->usbReceive.capacity = 0;
 
+        // wMaxPacketSize
+        newdevice->wMaxPacketSize = 64;
+
         // Initialize libusb
         usb_init();
         usb_find_busses();
@@ -328,7 +350,7 @@ int usbmux_get_specific_device(int bus_n, int dev_n,
                                 if (strtol(dev->filename, NULL, 10) == dev_n) {
                                         newdevice->__device = dev;
                                         newdevice->usbdev = usb_open(newdevice->__device);
-                                        if (!newdevice->usbdev) {
+                                        if (!newdevice->usbdev) {
                                                 fprintf(stderr, "%s: Error: usb_open(): %s\n", __func__, usb_strerror());
                                         }
                                         if (usbmux_config_usb_device(newdevice) == 0) {
@@ -495,6 +517,15 @@ if (toto_debug > 0) {
                         datalen -= bytes;
                         continue;
                 }
+                if ((bytes % device->wMaxPacketSize) == 0) {
+                        log_debug_msg("NOTE: sending NULL packet\n");
+                        char nullp = 0;
+                        int res = usb_bulk_write(device->usbdev, BULKOUT,
+                                                &nullp, 0, timeout);
+                        if (res < 0) {
+                            log_debug_msg("ERROR: NULL packet write returned %d\n", res);
+                        }
+                }
         } while (0);                            // fall out
 
         if (bytes > 0) {