And one more comment:

>interrupts ... are _not_ "per-device," but rather "per-bus" on many systems

True; evcnt's were not intended to replace everything, but rather
to fix up ugly hardwiring of things like `vector 0x240007 is the
console unless the CPU is a Blorch-325'.  If the hardware has a
fixed, regular set of interrupts that can be counted & handled in
common code, they probably should be.

Chris