Hang at startup on Sony Vaio with 5.3-CURRENT

This is really a message from Jack Twilley <jmt_at_twilley.org>,
but he has sent the message multiple times and neither of us
have seen it show up in the -current mailing list.  I (Garance)
seem to remember someone else reporting a similar problem.
I *think* it might have been Bruce Mah, but I am not sure.

                    - Garance
   - - - -

I have a Sony Vaio notebook (PCG-V505DXP) which runs 5.2-CURRENT
but which hangs when booting 5.3-CURRENT or 6-CURRENT.

The hang occurs after the following bit:

   ata1-slave: FAILURE - ATAPI_IDENTIFY no interrupt
   ata1-slave: FAILURE - ATAPI_IDENTIFY no interrupt

On 5.2-CURRENT, the CD drive is immediately detected after the
second message is displayed and the boot continues normally.  On
5.3-CURRENT and 6-CURRENT, the system hangs for at least an hour.

The CD drive in question:

   acd0: CDRW <UJDA745 DVD/CDRW> at ata1-master PIO4

The working kernel:

FreeBSD jmt-work.twilley.org 5.2-CURRENT FreeBSD
                  5.2-CURRENT #0: Tue Jul  6 10:35:02 PDT 2004 
root_at_jmt-work.twilley.org:/usr/obj/usr/src/sys/JMT-WORK  i386

The failing kernels:

FreeBSD 6.0-CURRENT #14: Tue Oct  5 12:59:43 PDT 2004
FreeBSD 5.3-STABLE  #17: Wed Oct 20 14:19:31 PDT 2004

The config file is available at
http://www.twilley.org/~jmt/tmp/jmt-work.txt
if that is of interest.  The dmesg output from the working kernel
is also at http://www.twilley.org/~jmt/tmp/dmesg.txt

Please feel free to contact me if there's any more information
which I can supply.

Jack.