subdevice=PCI_ANY_ID, class=0, class_mask=0;
        unsigned long driver_data=0;
        int fields=0;
-       int retval;
+       int retval=0;
 
        fields = sscanf(buf, "%x %x %x %x %x %x %lx",
                        &vendor, &device, &subvendor, &subdevice,
 
        /* Only accept driver_data values that match an existing id_table
           entry */
-       retval = -EINVAL;
-       while (ids->vendor || ids->subvendor || ids->class_mask) {
-               if (driver_data == ids->driver_data) {
-                       retval = 0;
-                       break;
+       if (ids) {
+               retval = -EINVAL;
+               while (ids->vendor || ids->subvendor || ids->class_mask) {
+                       if (driver_data == ids->driver_data) {
+                               retval = 0;
+                               break;
+                       }
+                       ids++;
                }
-               ids++;
+               if (retval)     /* No match */
+                       return retval;
        }
-       if (retval)     /* No match */
-               return retval;
 
        dynid = kzalloc(sizeof(*dynid), GFP_KERNEL);
        if (!dynid)