avision: match also USB vendor and product ids for USB devices.

We always know the USB vendor and product ids for USB devices and
there are multiple entries with the same SCSI details shared by
different USB models. We should pick the correct one at least to
get the right model name to the user.

backend/avision.c

@@ -4373,41 +4373,82 @@ attach (SANE_String_Const devname, Avision_ConnectionType con_type,
 
   model_num = 0;
   found = 0;
-  /* while not at at end of list NULL terminator */
-  while (Avision_Device_List[model_num].real_mfg != NULL ||
-         Avision_Device_List[model_num].scsi_mfg != NULL)
-  {
-    int matches = 0, match_count = 0; /* count number of matches */
-    DBG (1, "attach: Checking model: %d\n", model_num);
 
-    if (Avision_Device_List[model_num].scsi_mfg) {
-      ++match_count;
-      if (strcmp(mfg, Avision_Device_List[model_num].scsi_mfg) == 0)
-        ++matches;
-    }
-    if (Avision_Device_List[model_num].scsi_model) {
-      ++match_count;
-      if (strcmp(model, Avision_Device_List[model_num].scsi_model) == 0)
-        ++matches;
-    }
+  /*
+   * Search for a matching device in the device list.
+   * Primarily we need two matches for SCSI devices.
+   * However, multiple USB device entries share the same
+   * SCSI info. For USB devices, we will also do a mandatory
+   * USB Product/Vendor check to pick the right one. Otherwise
+   * at the very least the device name is incorrect.
+   *
+   */
+  SANE_Word usb_vendor = 0;
+  SANE_Word usb_product = 0;
 
-    /* we need 2 matches (mfg, model) for SCSI entries, or the ones available
-       for "we know what we are looking for" USB entries */
-    if ((attaching_hw == &(Avision_Device_List [model_num]) &&
-         matches == match_count) ||
-	matches == 2)
+  if (con_type == AV_USB)
     {
-      DBG (1, "attach: Scanner matched entry: %d: \"%s\", \"%s\", 0x%.4x, 0x%.4x\n",
-           model_num,
-	   Avision_Device_List[model_num].scsi_mfg,
-	   Avision_Device_List[model_num].scsi_model,
-	   Avision_Device_List[model_num].usb_vendor,
-	   Avision_Device_List[model_num].usb_product);
-      found = 1;
-      break;
+      status = sanei_usb_get_vendor_product_byname (devname, &usb_vendor, &usb_product);
+      if (status != SANE_STATUS_GOOD)
+        {
+          DBG (0, "attach: Could not retrieve USB vendor nor product for USB device.\n");
+          status = SANE_STATUS_INVAL;
+          goto close_scanner_and_return;
+        }
+    }
+
+  /* while not at at end of list NULL terminator */
+  while (Avision_Device_List[model_num].real_mfg != NULL
+      || Avision_Device_List[model_num].scsi_mfg != NULL)
+    {
+      int matches = 0, match_count = 0; /* count number of matches */
+      DBG (1, "attach: Checking model: %d\n", model_num);
+
+      if (Avision_Device_List[model_num].scsi_mfg)
+        {
+          ++match_count;
+          if (strcmp (mfg, Avision_Device_List[model_num].scsi_mfg) == 0)
+            ++matches;
+        }
+      if (Avision_Device_List[model_num].scsi_model)
+        {
+          ++match_count;
+          if (strcmp (model, Avision_Device_List[model_num].scsi_model) == 0)
+            ++matches;
+        }
+
+      /*
+       * Must match on USB vendor product also for USB devices.
+       * We will *always* know the vendor and product for USB devices.
+       *
+       */
+      if (con_type == AV_USB)
+        {
+          ++match_count;
+          if ((Avision_Device_List[model_num].usb_product == usb_product)
+              && (Avision_Device_List[model_num].usb_vendor == usb_vendor))
+            {
+              ++matches;
+            }
+        }
+
+      /* we need 2 matches (mfg, model) for SCSI entries, or the ones available
+       for "we know what we are looking for" USB entries */
+      if ((attaching_hw == &(Avision_Device_List[model_num]))
+          && (matches == match_count))
+        {
+          DBG (
+              1,
+              "attach: Scanner matched entry: %d: \"%s\", \"%s\", 0x%.4x, 0x%.4x\n",
+              model_num, Avision_Device_List[model_num].scsi_mfg,
+              Avision_Device_List[model_num].scsi_model,
+              Avision_Device_List[model_num].usb_vendor,
+              Avision_Device_List[model_num].usb_product);
+          found = 1;
+          break;
+        }
+      ++model_num;
     }
-    ++model_num;
-  }
 
   if (!found) {
     DBG (0, "attach: \"%s\" - \"%s\" not yet in whitelist!\n", mfg, model);