TDA4VM: srv component rendering lost

// If avmStatus is always 1, we got correct rendering result.
// If avmStatus(== 0) is input for about 10 minutes, then input avmStatus(== 1), we will get an incomplete rendering result.
void render_renderFrame(GLuint cameraTextures[4], int avmStatus)
{
    int offscreen_width = 1856;
    int offscreen_height = 750;

    GLint default_fbo;
    glGetIntegerv(GL_FRAMEBUFFER_BINDING, &default_fbo);

    // We bind an offscreen framebuffer offscreen_fbo whitch is created in srv init function.
    glBindFramebuffer(GL_FRAMEBUFFER, offscreen_fbo);

    // when avmStatus == 1 whitch means Active, we need to render a srv image for HDU.
    if(avmStatus == 1)
    {
       // we clear offscreen with Gray color.
        glClearColor(0.55f, 0.55f, 0.55f, 0.0f);
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

        // Now we setup viewports and draw camera textures, car models and other components to offscreen framebuffer.
        {
            // glViewport ...
            // glDrawArrays ...

            // glViewport ...
            // glDrawArrays ...

            // glViewport ...
            // glDrawArrays ...

            // glViewport ...
            // glDrawArrays ...

            // Finally we got surround-view image for HDU.
            //
        }
    }
    // otherwize(Inactive) we need to render a black image for HDU.
    else
    {
        // We clear offscreen with Black color.
        glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
        glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
    }

    glBindFramebuffer(GL_FRAMEBUFFER, default_fbo);

    glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
    glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);

    glViewport(0, 0, offscreen_width, offscreen_height);

    // Now we render offscreen_fbo texture attachment to default framebuffer.

    // ... ....
}

Thanks！

Henghui Guo