HMC5883 driver: stack size adjustments of start handler and start return review / comments

src/drivers/hmc5883/hmc5883.cpp

@@ -867,7 +867,7 @@ HMC5883::collect()
 	struct {
 		int16_t		x, y, z;
 	} report;
-	int	ret = -EIO;
+	int	ret;
 	uint8_t	cmd;
 	uint8_t check_counter;
 
@@ -1157,7 +1157,7 @@ int HMC5883::calibrate(struct file *filp, unsigned enable)
 out:
 
 	if (OK != ioctl(filp, MAGIOCSSCALE, (long unsigned int)&mscale_previous)) {
-		warn("WARNING: failed to set new scale / offsets for mag");
+		warn("failed to set new scale / offsets for mag");
 	}
 
 	/* set back to normal mode */
@@ -1353,6 +1353,9 @@ void	usage();
 
 /**
  * Start the driver.
+ *
+ * This function call only returns once the driver
+ * is either successfully up and running or failed to start.
  */
 void
 start(int bus, enum Rotation rotation)
@@ -1443,7 +1446,7 @@ test(int bus)
 	int fd = open(path, O_RDONLY);
 
 	if (fd < 0)
-		err(1, "%s open failed (try 'hmc5883 start' if the driver is not running", path);
+		err(1, "%s open failed (try 'hmc5883 start')", path);
 
 	/* do a simple demand read */
 	sz = read(fd, &report, sizeof(report));

src/drivers/hmc5883/module.mk

@@ -37,7 +37,6 @@
 
 MODULE_COMMAND	= hmc5883
 
-# XXX seems excessive, check if 2048 is sufficient
-MODULE_STACKSIZE	= 4096
-
 SRCS		= hmc5883.cpp
+
+MODULE_STACKSIZE	= 1200