From df5d702baefae7f51161d170c911cb398f418538 Mon Sep 17 00:00:00 2001
From: Anton Babushkin <anton.babushkin@me.com>
Date: Sun, 16 Mar 2014 17:03:39 +0400
Subject: [PATCH 1/2] mavlink: MavlinkOrbSubscription.update() result fixed

---
 src/modules/mavlink/mavlink_orb_subscription.cpp | 11 +++++++----
 src/modules/mavlink/mavlink_orb_subscription.h   | 13 +++++++------
 2 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/src/modules/mavlink/mavlink_orb_subscription.cpp b/src/modules/mavlink/mavlink_orb_subscription.cpp
index 9963184683..e8f9bb75ba 100644
--- a/src/modules/mavlink/mavlink_orb_subscription.cpp
+++ b/src/modules/mavlink/mavlink_orb_subscription.cpp
@@ -78,12 +78,15 @@ MavlinkOrbSubscription::get_data()
 bool
 MavlinkOrbSubscription::update(const hrt_abstime t)
 {
-	if (_last_check != t) {
+	if (_last_check == t) {
+		/* already checked right now, return result of the check */
+		return _updated;
+
+	} else {
 		_last_check = t;
-		bool updated;
-		orb_check(_fd, &updated);
+		orb_check(_fd, &_updated);
 
-		if (updated) {
+		if (_updated) {
 			orb_copy(_topic, _fd, _data);
 			return true;
 		}
diff --git a/src/modules/mavlink/mavlink_orb_subscription.h b/src/modules/mavlink/mavlink_orb_subscription.h
index 42d47e96ed..8529721c03 100644
--- a/src/modules/mavlink/mavlink_orb_subscription.h
+++ b/src/modules/mavlink/mavlink_orb_subscription.h
@@ -48,7 +48,7 @@
 class MavlinkOrbSubscription
 {
 public:
-	MavlinkOrbSubscription *next;
+	MavlinkOrbSubscription *next;	/*< pointer to next subscription in list */
 
 	MavlinkOrbSubscription(const orb_id_t topic);
 	~MavlinkOrbSubscription();
@@ -66,11 +66,12 @@ public:
 	const orb_id_t get_topic();
 
 private:
-	const orb_id_t _topic;
-	int _fd;
-	bool _published;
-	void *_data;
-	hrt_abstime _last_check;
+	const orb_id_t _topic;		/*< topic metadata */
+	int _fd;					/*< subscription handle */
+	bool _published;			/*< topic was ever published */
+	void *_data;				/*< pointer to data buffer */
+	hrt_abstime _last_check;	/*< time of last check */
+	bool _updated;				/*< updated on last check */
 };
 
 

From 762e8f52893afee6e8ffb6a728e5bc88518829c3 Mon Sep 17 00:00:00 2001
From: Anton Babushkin <anton.babushkin@me.com>
Date: Sun, 16 Mar 2014 17:28:34 +0400
Subject: [PATCH 2/2] mavlink_orb_subscription: minor optimization and comment
 fix

---
 src/modules/mavlink/mavlink_orb_subscription.cpp | 4 ++++
 src/modules/mavlink/mavlink_orb_subscription.h   | 2 +-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/modules/mavlink/mavlink_orb_subscription.cpp b/src/modules/mavlink/mavlink_orb_subscription.cpp
index e8f9bb75ba..4de7228324 100644
--- a/src/modules/mavlink/mavlink_orb_subscription.cpp
+++ b/src/modules/mavlink/mavlink_orb_subscription.cpp
@@ -98,6 +98,10 @@ MavlinkOrbSubscription::update(const hrt_abstime t)
 bool
 MavlinkOrbSubscription::is_published()
 {
+	if (_published) {
+		return true;
+	}
+
 	bool updated;
 	orb_check(_fd, &updated);
 
diff --git a/src/modules/mavlink/mavlink_orb_subscription.h b/src/modules/mavlink/mavlink_orb_subscription.h
index 8529721c03..5c6543e813 100644
--- a/src/modules/mavlink/mavlink_orb_subscription.h
+++ b/src/modules/mavlink/mavlink_orb_subscription.h
@@ -59,7 +59,7 @@ public:
 	 * Check if the topic has been published.
 	 *
 	 * This call will return true if the topic was ever published.
-	 * @param true if the topic has been published at least once.
+	 * @return true if the topic has been published at least once.
 	 */
 	bool is_published();
 	void *get_data();