INTR_FILTER?

[Andriy Gapon]

on 29/01/2009 14:55 Ed Schouten said the following:
> * Andriy Gapon <avg at icyb.net.ua> wrote:
>> INTR_FILTER - what does it do?
>> It doesn't seem to be documented anywhere, but seems to affect interrupt
>> code.
> 
> Not sure, but I think I was once told that FreeBSD has a `two level'
> interrupt handling scheme, where the filter is invoked directly to only
> figure out whether the interrupt is spurious or not. After it has been
> determined it is not, an interrupt thread is scheduled to handle the
> interrupt.
> 
> But as I said, I'm not sure. :-)
> 

This is true and is documented in bus_setup_intr(9).
But INTR_FILTER is a compile-time kernel option.

-- 
Andriy Gapon