On port-atari, I seem to have a problem handling ISDN interrupts. I should
handle them within 4ms and sometimes, that is condition is not met.
Since 4ms is quite some time, even on a 64MHz 68060, I suspect that someone
is blocking interrupts for a bit too long.

I was wondering if someone on this list has experience in tracking down these
kinds of problems. I'd like to share ideas...

Leo.