5.3-BETA2 boot hang, maybe acpi related

I have a problem similar to the 'hang during CDROM detection' thread that is
also going on right now. When I try to boot from either a 5.3-BETA2 CD or a
5.3-BETA2 installation on my hard drive, I experience a boot hang.

I have one hard drive with FreeBSD connected as the master drive on the
first PATA channel. I have an optical drive connected as the slave drive on
the second PATA channel. I have one drive connected to the first channel on
the SATA controller. I have the SATA controller selected in the BIOS as my
boot device. I have been booting FreeBSD via a boot menu on the SATA drive.

I get all the way to:

ad0: 8223MB <ST38410A/3.20) [16708/16/63] at ata0-master UDMA66
ATAPI_RESET time = 80us
acd0: CDRW <LITE-ON DVDRW LDW-811S/HS06> at ata1-slave UDMA33

At which point bootup hangs. If I boot with verbose logging, I can see that
ata2 gets reset a couple of times and then nothing. There may be other
interesting messages, but they pass too quickly for me to read.

If I disable ACPI, I can boot normally. If I disable my SATA controller, I
can boot normally. If I remove the drive connected to the SATA controller, I
can boot normally. 

This all worked fine with 5.2.1-RELEASE.

I think this might relate to pr/70925, so I posted a followup there also.

-Will