6-STABLE/amd64 recent kernel can't see any ata disks

[James Seward]

Hello list :)

I am having some issues with recent kernels since about the 6th Nov.
All kernels I have build since then have failed to boot, stopped at
the point they should mount root, and offering me a "mountroot>"
prompt to give the root device. Entering "?" at this prompt returns
something along the lines of:

List of GEOM-managed devices:
/dev/fd0

(The exact wording escapes me as I'm writing this at work and the
machine is at home.)

At this point, the HD LED on the computer and the floppy drive's LED
are stuck on.

I have tried several builds at various intervals since this problem
first showed up, including a complete fresh cvsup of /usr/src and
building GENERIC. (My custom kernel config did not change before the
problem surfaced.)

Unfortunately because of scroll I cannot see if the ata controllers
are detected during boot - but I am going to attempt to get a serial
cable onto the machine and grab the boot messages that way tonight.

The uname output for the working kernel is:
FreeBSD ... 6.0-STABLE FreeBSD 6.0-STABLE #6: Sun Nov  6 13:10:48 GMT
2005     root at ...:/usr/obj/usr/src/sys/MYCONF amd64

The motherboard is an Asus A8V-Deluxe and I have both SATA and PATA
disks attached to it - all of which work fine on the old kernel, and
also in Windows XP (which dual boots on that machine).

dmesg from a successful start:
http://sakaki.jamesoff.net/~james/dmesg-working.txt
pciconf -lv: http://sakaki.jamesoff.net/~james/pciconf.txt

Hopefully I can update this later with the dmesg from a newer kernel
failing to start. Any and all suggestions gratefully received :)

Cheers,
James