diff --git a/src/drivers/ets_airspeed/ets_airspeed.cpp b/src/drivers/ets_airspeed/ets_airspeed.cpp
index c15a0cee43..f98d615a2c 100644
--- a/src/drivers/ets_airspeed/ets_airspeed.cpp
+++ b/src/drivers/ets_airspeed/ets_airspeed.cpp
@@ -286,6 +286,9 @@ void	info();
 
 /**
  * Start the driver.
+ *
+ * This function only returns if the sensor is up and running
+ * or could not be detected successfully.
  */
 void
 start(int i2c_bus)
diff --git a/src/drivers/ets_airspeed/module.mk b/src/drivers/ets_airspeed/module.mk
index 15346c5c55..966a5b8190 100644
--- a/src/drivers/ets_airspeed/module.mk
+++ b/src/drivers/ets_airspeed/module.mk
@@ -36,6 +36,7 @@
 #
 
 MODULE_COMMAND		= ets_airspeed
-MODULE_STACKSIZE	= 2048
 
 SRCS			= ets_airspeed.cpp
+
+MODULE_STACKSIZE	= 1200
diff --git a/src/drivers/meas_airspeed/meas_airspeed.cpp b/src/drivers/meas_airspeed/meas_airspeed.cpp
index 07611f9039..d643fcad61 100644
--- a/src/drivers/meas_airspeed/meas_airspeed.cpp
+++ b/src/drivers/meas_airspeed/meas_airspeed.cpp
@@ -420,6 +420,9 @@ void	info();
 
 /**
  * Start the driver.
+ *
+ * This function call only returns once the driver is up and running
+ * or failed to detect the sensor.
  */
 void
 start(int i2c_bus)
diff --git a/src/drivers/meas_airspeed/module.mk b/src/drivers/meas_airspeed/module.mk
index fed4078b63..84192d1b56 100644
--- a/src/drivers/meas_airspeed/module.mk
+++ b/src/drivers/meas_airspeed/module.mk
@@ -36,6 +36,7 @@
 #
 
 MODULE_COMMAND		= meas_airspeed
-MODULE_STACKSIZE	= 2048
 
 SRCS			= meas_airspeed.cpp
+
+MODULE_STACKSIZE	= 1200