Use cfsetispeed and cfsetospeed helpers to set bitrate.

chrome/browser/extensions/api/serial/serial_connection_posix.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/extensions/api/serial/serial_connection.h"
 
 #include <sys/ioctl.h>
 #include <termios.h>
 
 namespace extensions {
 
 bool SerialConnection::PostOpen() {
   struct termios options;
 
   // Start with existing options and modify.
   tcgetattr(file_, &options);
 
   // Bitrate (sometimes erroneously referred to as baud rate).
   if (bitrate_ >= 0) {
-    options.c_ispeed = bitrate_;
-    options.c_ospeed = bitrate_;
+    cfsetispeed(&options, bitrate_);
+    cfsetospeed(&options, bitrate_);
   }
 
   // 8N1
   options.c_cflag &= ~PARENB;
   options.c_cflag &= ~CSTOPB;
   options.c_cflag &= ~CSIZE;
   options.c_cflag |= CS8;
   options.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG);
 
   // Enable receiver and set local mode
@@ skipping 33 matching lines @@
     if (control_signals.rts)
       status |= TIOCM_RTS;
     else
       status &= ~TIOCM_RTS;
   }
 
   return ioctl(file_, TIOCMSET, &status) == 0;
 }
 
 }  // namespace extensions