VIDIOC_STREAMON: Bad file descriptor opencv 3.0

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VIDEOIO ERROR: V4L2: Pixel format of incoming image is unsupported by OpenCV
VIDIOC_STREAMON: Bad file descriptor

Good news bad news .... I modified mi cap_v4l.cpp file in order to set EXPOSURE_ABSOLUTE camera parameter ... all ok ... Anyhow ... since I installed opencv3.0 I can not turn off and turn on the camera repeatedly without closing my app .... first with opencv 2.4.9 we could (though I used another system ..)... the simple code that I use ...

if (!mo_cap.isOpened())
{
    VideoCapture mo_cap; // open the default camer
    mo_cap.open(0);
}


if (mo_cap.isOpened())
{
  do
  {

        QMutex mutex;
        mutex.lock();
        if(this->Stop) break;
        mutex.unlock();

        mo_cap.set(CV_CAP_PROP_GAIN, ex_gain);
        mo_cap.set(CV_CAP_PROP_EXPOSURE, ex_exposure_abs);


    controllokeypoint2 = 0;


    mo_cap >> dest_image1111;
    cvtColor(dest_image1111, dest_image, COLOR_BGR2RGB);
    dest_image1 = dest_image.clone();

    Mat2QImage(dest_image1); /**** these func send the video on Gui *******/

      this->msleep(30);
     }
       While(/*stop_capture button is checked*/)

        dest_image1111.release();
        dest_image1.release();
         dest_imag1111.release();
        mo_cap.release();

         qDebug() << "the camera thread is closed.";
       }


       /************** NEW PIECE OF CODE OUT OF QT *** EXAMPLE CPP MODIFICATION FOR RE-OPEN CAMERA*********/
        #include "opencv2/core.hpp"
#include "opencv2/imgproc.hpp"
#include "opencv2/highgui.hpp"
#include "opencv2/videoio.hpp"
#include <iostream>

using namespace cv;
using namespace std;

void drawText(Mat & image);
char key = (char) cv::waitKey(30); 
int test = 0;

int main()
{


    cout << "Built with OpenCV " << CV_VERSION << endl;
    Mat image;
    Mat image1;
    VideoCapture mo_cap;
    VideoCapture mo_cape;
    mo_cap.open(0);



    mo_cap.set(CV_CAP_PROP_EXPOSURE, 450 );
    mo_cap.set(CV_CAP_PROP_GAIN, 130 );


for (;;)
{

            if(cv::waitKey(1) == 32) 
     {
    cout << "Built with OpenCV " << CV_VERSION << endl;
        Mat image;
        Mat image1;

       mo_cape.open(0);
        mo_cape.set(CV_CAP_PROP_EXPOSURE, 450 );
        mo_cape.set(CV_CAP_PROP_GAIN, 130 );
         test = 1;
    }

    if(mo_cap.isOpened() || mo_cape.isOpened())
    {
        cout << "Capture is opened" << endl;
        for(;;) 
       {
            if(test == 0){mo_cap >> image;}
            else {mo_cape >> image;}
            cvtColor(image, image1, COLOR_BGR2RGB);
            if(image1.empty())
                break;
            //drawText(image);
            imshow("Sample", image1);
            if(cv::waitKey(1) == 8) {mo_cap.release(); break;}

        }

          mo_cap.release();
    }
    else
    {
        cout << "No capture" << endl;
        image = Mat::zeros(480, 640, CV_8UC1);
        image1 = Mat::zeros(480, 640, CV_8UC1);
        drawText(image1);
        imshow("Sample", image);
        //if(Key == 27) break;
    }

  if(cv::waitKey(1) == 27) break;
}

    return 0;
}

void drawText(Mat & image1)
{
    putText(image1, "Hello OpenCV",Point(20, 50),FONT_HERSHEY_COMPLEX, 1,Scalar(255, 255, 255),1, LINE_AA); 
}

I'm on linux kernel 4.4.041 all is installed ok ... when I try run again my thread obtain these error ...

VIDEOIO ERROR: V4L2: Pixel format of incoming image is unsupported by OpenCV
 VIDIOC_STREAMON: Bad file descriptor
 VIDIOC_STREAMON: Bad file descriptor
 VIDIOC_STREAMON: Bad file descriptor  /**** one for every thread cicle*****/
 /******************ERROR WITH C++ OPENCV CODE OUT OF QT***********************/
 VIDEOIO ERROR: V4L2: Pixel format of incoming image is unsupported by OpenCV
  Capture is opened
   VIDIOC_STREAMON: Bad file descriptor
  OpenCV Error: Assertion failed (scn == 3 || scn == 4) in cvtColor, file /home/opencv-3.0.0/modules/imgproc/src/color.cpp, line 7349
   terminate called after throwing an instance of 'cv::Exception'
   what():  /home/opencv-3.0.0/modules/imgproc/src/color.cpp:7349: error: (-215) scn == 3 || scn == 4 in function cvtColor

   Destroy

All type of suggest is well accept ...

Regards giorgio