init.d-posix: raise timeouts for fast SITL

When simulating with lockstep we can raise the speed by setting the env
variable `PX4_SIM_SPEED_FACTOR`. Some inputs like RC, MAVLink heartbeats
from a ground station, or offboard controls via MAVLink are still at the
normal speed which leads to timeouts getting detected in PX4.

To work around this issue we can automatically multiply the timeout
parameters by the speed factor.

ROMFS/px4fmu_common/init.d-posix/rcS

@@ -160,6 +160,21 @@ then
 	param set WEST_EN 0
 fi
 
+# Adapt timeout parameters if simulation runs faster or slower than realtime.
+if [ ! -z $PX4_SIM_SPEED_FACTOR ]; then
+	COM_DL_LOSS_T_LONGER=$(($PX4_SIM_SPEED_FACTOR * 10))
+	echo "COM_DL_LOSS_T set to $COM_DL_LOSS_T_LONGER"
+	param set COM_DL_LOSS_T $COM_DL_LOSS_T_LONGER
+
+	COM_RC_LOSS_T_LONGER=$(($PX4_SIM_SPEED_FACTOR * 1))
+	echo "COM_RC_LOSS_T set to $COM_RC_LOSS_T_LONGER"
+	param set COM_RC_LOSS_T $COM_RC_LOSS_T_LONGER
+
+	COM_OF_LOSS_T_LONGER=$(($PX4_SIM_SPEED_FACTOR * 10))
+	echo "COM_OF_LOSS_T set to $COM_OF_LOSS_T_LONGER"
+	param set COM_OF_LOSS_T $COM_OF_LOSS_T_LONGER
+fi
+
 # Autostart ID
 autostart_file=''
 for f in etc/init.d-posix/"$(param show -q SYS_AUTOSTART)"_*