title: Check OpenCL version compatibilty correctly?
body: <p>My application is OpenCL 1.1 compatiable and I want to check whether each of the device has drivers for that version. There are 2 ways for this:</p>
  
  <ol>
  <li>clGetDeviceInfo() ->CL_DEVICE_VERSION</li>
  <li>clGetPlatformInfo() ->CL_PLATFORM_VERSION</li>
  </ol>
  
  <p>I have following doubts:</p>
  
  <ul>
  <li>I do not understand why method 1 is provided as method 2 seems the
  correct way to me?</li>
  <li>Is it possible that the version given by the    platform will not
  match with the version given by a device from the    same platform?</li>
  <li>What is clGetDeviceInfo::CL_DRIVER_VERSION for?</li>
  <li>From all these options which one should I use to check if a device
  can run my OpenCL 1.1 code?</li>
  </ul>