From f1f1ecd096f2ad7b791127c9ee943a7dfc0ab3f4 Mon Sep 17 00:00:00 2001
From: Lorenz Meier <lm@inf.ethz.ch>
Date: Tue, 18 Feb 2014 10:36:46 +0100
Subject: [PATCH] Fix mavlink feedback FD handling

---
 src/drivers/px4io/px4io.cpp | 27 ++++++++++++---------------
 1 file changed, 12 insertions(+), 15 deletions(-)

diff --git a/src/drivers/px4io/px4io.cpp b/src/drivers/px4io/px4io.cpp
index efcf4d12b9..13326e9625 100644
--- a/src/drivers/px4io/px4io.cpp
+++ b/src/drivers/px4io/px4io.cpp
@@ -244,8 +244,7 @@ private:
 	volatile int		_task;			///< worker task id
 	volatile bool		_task_should_exit;	///< worker terminate flag
 
-	int			_mavlink_fd;		///< mavlink file descriptor. This is opened by class instantiation and Doesn't appear to be usable in main thread.
-	int			_thread_mavlink_fd;	///< mavlink file descriptor for thread.
+	int			_mavlink_fd;		///< mavlink file descriptor.
 
 	perf_counter_t		_perf_update;		///<local performance counter for status updates
 	perf_counter_t		_perf_write;		///<local performance counter for PWM control writes
@@ -474,7 +473,6 @@ PX4IO::PX4IO(device::Device *interface) :
 	_task(-1),
 	_task_should_exit(false),
 	_mavlink_fd(-1),
-	_thread_mavlink_fd(-1),
 	_perf_update(perf_alloc(PC_ELAPSED, "io update")),
 	_perf_write(perf_alloc(PC_ELAPSED, "io write")),
 	_perf_chan_count(perf_alloc(PC_COUNT, "io rc #")),
@@ -507,9 +505,6 @@ PX4IO::PX4IO(device::Device *interface) :
 	/* we need this potentially before it could be set in task_main */
 	g_dev = this;
 
-	/* open MAVLink text channel */
-	_mavlink_fd = ::open(MAVLINK_LOG_DEVICE, 0);
-
 	_debug_enabled = false;
 	_servorail_status.rssi_v = 0;
 }
@@ -785,7 +780,7 @@ PX4IO::task_main()
 	hrt_abstime poll_last = 0;
 	hrt_abstime orb_check_last = 0;
 
-	_thread_mavlink_fd = ::open(MAVLINK_LOG_DEVICE, 0);
+	_mavlink_fd = ::open(MAVLINK_LOG_DEVICE, 0);
 
 	/*
 	 * Subscribe to the appropriate PWM output topic based on whether we are the
@@ -880,6 +875,10 @@ PX4IO::task_main()
 			/* run at 5Hz */
 			orb_check_last = now;
 
+			/* try to claim the MAVLink log FD */
+			if (_mavlink_fd < 0)
+				_mavlink_fd = ::open(MAVLINK_LOG_DEVICE, 0);
+
 			/* check updates on uORB topics and handle it */
 			bool updated = false;
 
@@ -1275,16 +1274,14 @@ void
 PX4IO::dsm_bind_ioctl(int dsmMode)
 {
 	if (!(_status & PX4IO_P_STATUS_FLAGS_SAFETY_OFF)) {
-		/* 0: dsm2, 1:dsmx */
-		if ((dsmMode == 0) || (dsmMode == 1)) {
-			mavlink_log_info(_thread_mavlink_fd, "[IO] binding dsm%s rx", (dsmMode == 0) ? "2" : ((dsmMode == 1) ? "x" : "x8"));
-			ioctl(nullptr, DSM_BIND_START, (dsmMode == 0) ? DSM2_BIND_PULSES : ((dsmMode == 1) ? DSMX_BIND_PULSES : DSMX8_BIND_PULSES));
-		} else {
-			mavlink_log_info(_thread_mavlink_fd, "[IO] invalid dsm bind mode, bind request rejected");
-		}
+		mavlink_log_info(_mavlink_fd, "[IO] binding DSM%s RX", (dsmMode == 0) ? "2" : ((dsmMode == 1) ? "-X" : "-X8"));
+		int ret = ioctl(nullptr, DSM_BIND_START, (dsmMode == 0) ? DSM2_BIND_PULSES : ((dsmMode == 1) ? DSMX_BIND_PULSES : DSMX8_BIND_PULSES));
+
+		if (ret)
+			mavlink_log_critical(_mavlink_fd, "binding failed.");
 
 	} else {
-		mavlink_log_info(_thread_mavlink_fd, "[IO] system armed, bind request rejected");
+		mavlink_log_info(_mavlink_fd, "[IO] system armed, bind request rejected");
 	}
 }