AHC - 29160 interrupts not functioning?

[Patrick Hess]

Michael Butler wrote:
> Do you have "options AHC_ALLOW_MEMIO" in your kernel config?

I'm running GENERIC on all of those machines, and as far as I can tell,
that option is not enabled by default, at least on 10.1-RELEASE:

    # config -x /boot/kernel/kernel | grep -i ahc
    options AHC_REG_PRETTY_PRINT
    device  ahci
    device  ahc
    # uname -v
    FreeBSD 10.1-RELEASE-p16 #0: Tue Jul 28 11:41:12 UTC 2015     root at amd64-builder.daemonology.net:/usr/obj/usr/src/sys/GENERIC

> The machine I have running is an old Dell PowerApp 100 (700MHz
> Pentium-III) running about 4 jails :-(

Have you tried running an off-the-shelf GENERIC kernel on that machine?
I have an even older Primergy server (450 MHz Pentium-II) that runs my
backup system, and a 10.1-RELEASE GENERIC kernel works perfectly fine
on that ancient box, too. 

Patrick