v4l2 device needs replugging on app restart

Question

I have a simple c++ program where something like the following code is running in a thread to get a constant webcam feed. The first time everything works as expected. But after closing the application and running it again. The select() function times out and I never get a frame from the camera. Though the LED lights up as it should. The camera is usable without replugging within any other wecam application. It looks like my code is not properly resetting or shutting down?

fd = v4l2_open("/dev/video0", O_RDWR | O_NONBLOCK, 0);

// check if device is ready
v4l2_capability capability{};
ioctl(fd, VIDIOC_QUERYCAP, &capability);

// set Image format
v4l2_format imageFormat;
imageFormat.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
imageFormat.fmt.pix.width = s.width;
imageFormat.fmt.pix.height = s.height;
imageFormat.fmt.pix.pixelformat = V4L2_PIX_FMT_MJPEG;
imageFormat.fmt.pix.field = V4L2_FIELD_NONE;
// tell the device you are using this format
ioctl(fd, VIDIOC_S_FMT, &imageFormat);

v4l2_requestbuffers req{};
req.count = buffers.size();
req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
req.memory = V4L2_MEMORY_MMAP;

xioctl(fd, VIDIOC_REQBUFS, &req);

for (unsigned i = 0; i < req.count; i++) {
    // query buffer
    v4l2_buffer buf{};
    buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    buf.memory = V4L2_MEMORY_MMAP;
    buf.index = i;
    xioctl(fd, VIDIOC_QUERYBUF, &buf);

    // map data to buffer
    auto b = v4l2_mmap(nullptr, buf.length, PROT_READ | PROT_WRITE, MAP_SHARED, fd, buf.m.offset);
    buffers[i].start = reinterpret_cast<uint8_t *>(b);
    buffers[i].length = buf.length;
}

for (unsigned i = 0; i < req.count; i++) {
    v4l2_buffer buf{};
    buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    buf.memory = V4L2_MEMORY_MMAP;
    buf.index = i;
    xioctl(fd, VIDIOC_QBUF, &buf);
}

auto type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
xioctl(fd, VIDIOC_STREAMON, &type);

while (bKeepRunning) {
    fd_set fds;
    timeval tv{};
    int r;

    FD_ZERO(&fds);
    FD_SET(fd, &fds);

    /* Timeout. */
    tv.tv_sec = 1;
    tv.tv_usec = 0;

    r = select(fd + 1, &fds, NULL, NULL, &tv);

    if (r <= 0) {
        continue;
    }

    v4l2_buffer buf{};

    buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    buf.memory = V4L2_MEMORY_MMAP;

    // retreive buffer
    if (-1 == xioctl(fd, VIDIOC_DQBUF, &buf)) {
        continue;
    }

    int jpegSubsamp, jpegW, jpegH;
    auto start = buffers[buf.index].start;
    auto data = jpgd::decompress_jpeg_image_from_memory(start, buf.bytesused, &jpegW, &jpegH, &jpegSubsamp, 3);

    // release buffer
    xioctl(fd, VIDIOC_QBUF, &buf);
}

xioctl(fd, VIDIOC_STREAMOFF, &type);

for (auto &buffer: buffers) {
    if (buffer.length == 0) continue;
    v4l2_munmap(buffer.start, buffer.length);
}
v4l2_close(fd);