title: For a shared interrupt line how do I find which interrupt handler to use?
body: <p>For a shared interrupt line,I can have several interrupt handlers. The kernel will sequentially invoke all the handlers for that particular shared line.
  As far as I know, each handler, when invoked informs the kernel whether it was the correct handler to be invoked or not.</p>
  
  <p>My questions is how is this determined,is there a way it checks a memory mapped register that tells status of a particular device or is there some other hardware mechanism ? How does the handler know that the corresponding device is indeed the one that issued the interrupt or not ?</p>
  
  <p>Is this information relayed through the interrupt controller that is between the devices and the processor interrupt line ??</p>