title: What does "console [ttyS0] enabled mean?
body: <p>I am trying to communicate between a single board computer and a PC over COM ports. On the single board computer I am running Debian Linux and there are two UARTs that I can use. On one of the UARTs (<strong>ttyS1</strong>) I can communicate (send and receive) with no problems. When I try to communicate on the other UART (<strong>ttyS0</strong>) the send works perfectly however the receive <em>loses the 1st byte</em> in (sends an error message to the console on the PC saying that the character that is typed is not a command) and then all future characters are received correctly.</p>
  
  <p>If I switch from receiving to sending and then back to receiving the same occurs. If I stay in receive mode I can receive characters for as long as I want with no data loss. It appears that the transitioning from send to receive is causing this to happen. </p>
  
  <p>As I mentioned earlier I do not see this issue on the other UART (ttyS1). I started looking for reasons why the two ports are different. I used the same program to set up send and receive for both UARTS so the problem is not in the program setup. One thing that I did find when I typed the command <code>dmesg |grep tty</code> I get the following:</p>
  
  <pre><code>[    0.000000] Kernel command line: console=ttyS0,115200 root=/dev/mmcblk0p2 roo twait loglevel=8 panic=10
  [    0.446780] sunxi-uart.1: ttyS0 at MMIO 0x1c28400 (irq = 2) is a U6_16550A
  [    1.114996] console [ttyS0] enabled
  [    1.154643] sunxi-uart.3: ttyS1 at MMIO 0x1c28c00 (irq = 4) is a U6_16550A
  </code></pre>
  
  <p>I see that ttyS0 has the "console [ttyS0] enabled" associated with it where the ttyS1 does not. I was wondering what the "console [ttyS0] enabled means?</p>
  
  <p>Also, is there a way to disable it to see if this is what is causing my 'first byte of data loss'? I see in my setup for the single board computer that ttyS0 is designated the "debug port'.</p>
  
  <p>I was also wondering if that is analogous to console?</p>
  
  <p>Can someone please explain what having the console enabled implies?</p>