No disks found on FreeBSD 8.1-STABLE on Sun X4500

[Sean Caron]

Hi folks,

I've been contracted to try and get FreeBSD up and running on a Sun Fire 
X4500 "thumper" type system. It's been claimed as far back as 2007 that 
this system is apparently supported with no major issues:

http://lists.freebsd.org/pipermail/freebsd-fs/2007-May/003165.html

However in trying both FreeBSD 8.1-RELEASE, 8.1-STABLE (9/2010), and 
7.3-STABLE (9/2010), I am getting the exact same failure mode as this 
fellow:

http://forums.freebsd.org/showthread.php?t=14887

The system boots up, I don't see anything pertaining to disks at all in 
the boot messages, and, unsurprisingly the installer claims that no disks 
are found.

I've tried this just booting normally, hitting "6" at the boot menu and 
manually loading the mvs driver:

load mvs
boot

Nothing works. I've tried disabling ACPI but that just causes FreeBSD to 
hang at boot.

Tried falling back to 7.x-STABLE in the hopes that it would contain the 
pre-mvs SATA driver and that might work better but seems no results there.

Tried re-scanning devices in the installer but it fails just as the poster 
on the forums reports - takes a second and nothing new ever comes up.

Though I haven't actually verified this booting with something else e.g. 
Linux and looking at the PCI information, my understanding is that this 
system is based on the Marvell MV88SX6081 SATA controller which seems to 
be supported from looking at the source code of the mvs driver. The PCI ID 
string for this controller, 0x608111ab, is right there in the source. This 
isn't even a particularly new piece of hardware.

Is there anyone out there who has a Sun Fire X4500 up and running OK with 
FreeBSD? If so - what's the secret? Is there something in the BIOS that I 
need to flip? Maybe there are different revs of this hardware each with a 
different SATA controller chip?

I'm really interested in working in concert with someone in the know to do 
whatever it takes to hopefully get this resolved; if anyone can lend a 
hand please drop me a line.

Thanks,

-Sean