On Tuesday 21 July 2009, Thomas Gleixner wrote:

quoted

quoted

 - Multi-function devices like the twl4030 which have an interrupt
   controller on them and would like to expose that interrupt controller
   via the generic IRQ subsystem.  This was a large part of the
   discussion in the thread above is a much trickier problem.

Why ?

Because the current threaded IRQ framework stops short of supporting
the relevant IRQ chaining mechanisms.

It handles the first level IRQ.  Not the second or third level
which needs to be dispatched from that one.

- Dave