--- include/HidUps.h.orig	2015-02-08 18:00:05 UTC
+++ include/HidUps.h
@@ -107,6 +107,7 @@ class HidUps (private)
    /* Fetch a descriptor from an interface (as opposed to from the device) */
    int GetIntfDescr(
       unsigned char type, unsigned char index, void *buf, int size);
+   int GetIntfDescrLength(unsigned char index);
 
    bool init_device(struct usb_device *dev, const char *serno);
 
--- src/libusbhid/HidUps.cpp.orig	2015-02-08 18:00:05 UTC
+++ src/libusbhid/HidUps.cpp
@@ -244,6 +244,26 @@ int HidUps::GetIntfDescr(
                          (type << 8) + index, 0, (char*)buf, size, 1000);
 }
 
+/* Get the interface descriptor's length */
+int HidUps::GetIntfDescrLength(unsigned char index)
+{
+   /* usb_hid_descriptor  */
+   char buf[9];
+   memset(buf, 0, sizeof(buf));
+   int ret = usb_control_msg(_fd, USB_ENDPOINT_IN | USB_RECIP_INTERFACE,
+                            USB_REQ_GET_DESCRIPTOR,
+                            (USB_DT_HID << 8) + index, 0, (char*)buf, sizeof(buf), 1000);
+   
+   int len = MAX_SANE_DESCRIPTOR_LEN;
+   if (ret >= 0) {
+      /* wDescriptorLength */
+      int desclen = buf[7] | (buf[8] << 8);
+      if (desclen > 0)
+         len = desclen;
+   }
+   return len;
+}
+
 /*
  * Fetch the report descriptor from the device given an _fd for the
  * device's control endpoint. Descriptor length is written to the
@@ -255,8 +275,9 @@ unsigned char *HidUps::FetchReportDescr(int *rlen)
    unsigned char *ptr;
    int rdesclen;
 
-   ptr = (unsigned char*)malloc(MAX_SANE_DESCRIPTOR_LEN);
-   rdesclen = GetIntfDescr(USB_DT_REPORT, 0, ptr, MAX_SANE_DESCRIPTOR_LEN);
+   int desclen = GetIntfDescrLength(0);
+   ptr = (unsigned char*)malloc(desclen);
+   rdesclen = GetIntfDescr(USB_DT_REPORT, 0, ptr, desclen);
    if (rdesclen <= 0) {
       Dmsg(100, "Unable to get REPORT descriptor (%d).\n", rdesclen);
       free(ptr);