title: VideoCapture fails with camera in USB 3.0 port
body: <p>Why does the following code work when my camera is connected to a USB 2.0 port, but when the camera is connected to a USB 3.0 port I get the "No Camera" error? I am running OpenCV 2.4 on Ubuntu 12.04 LTE 32 bit. I've seen this problem with <a href="https://stackoverflow.com/questions/22390324/point-grey-firefly-mv-dc1394-and-usb-3-0">other cameras and drivers</a> also, so I suspect it might be a problem with Linux</p>
  
  <pre><code>#include &lt;stdio.h&gt;
  #include "opencv2/highgui/highgui.hpp"
  #include "opencv2/core/core.hpp"
  
  using namespace cv;
  
  int main(){
  
      Mat img;
      int imgw = 640;
      int imgh = 480;
  
      VideoCapture cap(0); // open the default camera
      if(!cap.isOpened()){ // check if we succeeded
          printf("No camera\n");
          return -1;
      }
      cap.set(CV_CAP_PROP_FRAME_WIDTH,  imgw);
      cap.set(CV_CAP_PROP_FRAME_HEIGHT, imgh);
  
      namedWindow( "Display Image", CV_WINDOW_AUTOSIZE );
  
      for( ; ; ){
  
          cap.read( img );
  
          imshow( "Display Image", img );
  
          if( waitKey( 5 ) == 27 ) break;
  
      }
  
      return 0;
  
  };
  </code></pre>
  
  <p>EDIT:
  Also throws error through a USB 2.0 hub connected to a USB 3.0 port.</p>
  
  <p>EDIT 2:
  Actually, this code works once after a restart. After that, the camera no longer shows up in /dev nor in the output of lsusb. None the USB 3.0 ports on that card work after one run of the program above.</p>