title: Error OpenCV with CUDA using TBB for multiple GPUs
body: <p>My OpenCV CUDA program runs fine using a single NVidia 580GTX, but when using another, it gives the following error:</p>
  
  <blockquote>
    <p>OpenCV Error: Gpu API call (invalid device ordinal) in mallocPitch</p>
  </blockquote>
  
  <p>I know I need TBB to assign a GPU its job, but even though I installed OpenCV with TBB support (followed the willowgarage website), it says <strong>TBB support is required (CMake key 'WITH_TBB' must be true</strong>). Any help would really be appreciated since I need this to complete my computer science Master's project. </p>
  
  <p>Thanks!</p>