From 334a599b2d6a64e6168cdba1937692e9bf0b0379 Mon Sep 17 00:00:00 2001
From: Julian Oes <julian@oes.ch>
Date: Fri, 22 Nov 2019 16:11:19 +0100
Subject: [PATCH] vmount: tell user how to use vmount test

This confused me, so hopefully it will help the next user, e.g. me.
---
 src/modules/vmount/vmount.cpp | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/src/modules/vmount/vmount.cpp b/src/modules/vmount/vmount.cpp
index aec55f4466..d70eee9d45 100644
--- a/src/modules/vmount/vmount.cpp
+++ b/src/modules/vmount/vmount.cpp
@@ -1,6 +1,6 @@
 /****************************************************************************
  *
- *   Copyright (c) 2013-2017 PX4 Development Team. All rights reserved.
+ *   Copyright (c) 2013-2019 PX4 Development Team. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -432,12 +432,21 @@ int vmount_main(int argc, char *argv[])
 		return -1;
 	}
 
-	if (!strcmp(argv[1], "start") || !strcmp(argv[1], "test")) {
+	const bool found_start = !strcmp(argv[1], "start");
+	const bool found_test = !strcmp(argv[1], "test");
+
+	if (found_start || found_test) {
 
 		/* this is not an error */
 		if (thread_running) {
-			PX4_WARN("mount driver already running");
-			return 0;
+			if (found_start) {
+				PX4_WARN("mount driver already running");
+				return 0;
+
+			} else {
+				PX4_WARN("mount driver already running, run vmount stop before 'vmount test'");
+				return 1;
+			}
 		}
 
 		thread_should_exit = false;