Fixed baud rate switching:

- added missing call of tcsetattr
- handle return values
- adjust timeout correctly

mbus/mbus-serial.c

@@ -75,7 +75,7 @@ mbus_serial_connect(char *device)
     // For 2400Bd this means (330 + 11) / 2400 + 0.05 = 188.75 ms (added 11 bit periods to receive first byte).
     // I.e. timeout of 0.2s seems appropriate for 2400Bd.
 
-    handle->t.c_cc[VTIME] = 2;
+    handle->t.c_cc[VTIME] = 2; // Timeout in 1/10 sec
 
     cfsetispeed(&(handle->t), B2400);
     cfsetospeed(&(handle->t), B2400);
@@ -93,39 +93,61 @@ mbus_serial_connect(char *device)
 }
 
 //------------------------------------------------------------------------------
-// 
+// Set baud rate for serial connection
 //------------------------------------------------------------------------------
 int
 mbus_serial_set_baudrate(mbus_serial_handle *handle, int baudrate)
 {
+    speed_t speed;
+
     if (handle == NULL)
         return -1;
 
     switch (baudrate)
     {
         case 300:
-            cfsetispeed(&(handle->t), B300);
-            cfsetospeed(&(handle->t), B300);
-            return 0;
+            speed = B300;
+            handle->t.c_cc[VTIME] = 12; // Timeout in 1/10 sec
+            break;
 
         case 1200:
-            cfsetispeed(&(handle->t), B1200);
-            cfsetospeed(&(handle->t), B1200);
-            return 0;
+            speed = B1200;
+            handle->t.c_cc[VTIME] = 4;  // Timeout in 1/10 sec
+            break;
 
         case 2400:
-            cfsetispeed(&(handle->t), B2400);
-            cfsetospeed(&(handle->t), B2400);
-            return 0;
+            speed = B2400;
+            handle->t.c_cc[VTIME] = 2;  // Timeout in 1/10 sec
+            break;
 
         case 9600:
-            cfsetispeed(&(handle->t), B9600);
-            cfsetospeed(&(handle->t), B9600);
-            return 0;
+            speed = B9600;
+            handle->t.c_cc[VTIME] = 1;  // Timeout in 1/10 sec
+            break;
 
        default:
-       return -1; // unsupported baudrate
+            return -1; // unsupported baudrate
     }
+
+    // Set input baud rate
+    if (cfsetispeed(&(handle->t), speed) != 0)
+    {
+        return -1;
+    }
+
+    // Set output baud rate
+    if (cfsetospeed(&(handle->t), speed) != 0)
+    {
+        return -1;
+    }
+
+    // Change baud rate immediately
+    if (tcsetattr(handle->fd, TCSANOW, &(handle->t)) != 0)
+    {
+        return -1;
+    }
+
+    return 0;
 }