title: cuda-gdb can't see available devices
body: <p>I'm trying to use cuda-gdb debug my code on a remote cluster via ssh. There're 6 Tesla C2070 gpu on the node:</p>
  
  <pre><code>$ deviceQuery | grep "^Device"
  Device 0: "Tesla C2070"
  Device 1: "Tesla C2070"
  Device 2: "Tesla C2070"
  Device 3: "Tesla C2070"
  Device 4: "Tesla C2070"
  Device 5: "Tesla C2070"
  </code></pre>
  
  <p>But when I run code under cuda-gdb, it still gives me error code=24: 
  "fatal:  All CUDA devices are used for display and cannot be used while debugging. "</p>
  
  <p>I've already set <code>-gencode arch=compute_20,code=sm_20</code> and compiles well. When I type <code>info cuda devices</code> in the debugger, it spits <code>No CUDA devices</code>. I also tried export <code>CUDA_VISIBLE_DEVICES="0,2"</code> but still not working. What should I do?
  I'm using cuda 5.0. Thanks in advance. </p>