title: problems to connect GDB over an serial port to an KGDB build Kernel
body: <p><br/>
  i want to debug an MIPS linux driver from my 64bit suse machine over serial ttyS0. The used gdb works greate over LAN with the debugging of applications but not with kgdb over serial. I used this <a href="http://kernel.org/pub/linux/kernel/people/jwessel/kdb/index.html" rel="noreferrer">page</a> and a few more to start the debugging but without final results.</p>
  
  <p>My kernel is compiled with the following setting:<br/></p>
  
  <pre><code>CONFIG_MAGIC_SYSRQ=y
  CONFIG_HAVE_ARCH_KGDB=y
  CONFIG_KGDB=y
  CONFIG_KGDB_SERIAL_CONSOLE=y
  # CONFIG_KGDB_TESTS is not set
  CONFIG_CMDLINE="kgdboc=ttyS0,115200"
  </code></pre>
  
  <p>if i run the gdb:</p>
  
  <pre><code>gdb vmlinux
  (gdb) set remotebaud 115200
  (gdb) set debug remote 1
  (gdb) target remote /dev/ttyS0
  </code></pre>
  
  <p>i can observe the following output:</p>
  
  <p>OUTPUT (GDB_TERMINAL):</p>
  
  <pre><code>(gdb) target remote /dev/ttyS0
  Remote debugging using /dev/ttyS0
  Sending packet: $qSupported:qRelocInsn+#9a...Ack
  Timeout in mid-packet, retrying
  Timed out.
  Timed out.
  Ignoring packet error, continuing...
  Packet qSupported (supported-packets) is supported
  warning: unrecognized item "qSupported:qRelocIns" in "qSupported" response
  Sending packet: $Hg0#df...Nak
  Sending packet: $Hg0#df...Ack
  Packet received: Hg0
  Sending packet: $?#3f...Packet instead of Ack, ignoring it
  Ack
  Timed out.
  Timed out.
  Timed out.
  Ignoring packet error, continuing...
  Sending packet: $Hc-1#09...Nak
  Sending packet: $Hc-1#09...Ack
  Reply contains invalid hex digit 36
  </code></pre>
  
  <p>OUTPUT (REMOTE_TARGET):</p>
  
  <pre><code>+$?#3f09n+#9a$Hg0#df+09
  </code></pre>
  
  <p>Nothing more happens!!!</p>
  
  <p>I also test the sysrq but the mentioned sysrq-option 'g' seems to do not to fit!</p>
  
  <pre><code>echo b &gt; /proc/sysrq-trigger 
  #successfully reboot
  
  echo g &gt; /proc/sysrq-trigger 
  #prints only the help message (SysRq : HELP : loglevel(0-9) reBoot Crash termin .....)
  </code></pre>
  
  <p>Is the sysrq running correctly?<br/>
  Is there somethin that i have missed?<br/>
  Exists there a way to test the running kgdb on my remote device?<br/></p>