Strange (repeatable) hang when ripping a CD

[jw]

Hello,

I am trying to use audio/ripit to rip an audio CD, but it results in a
system hang (no panic) every time.
Here is the tail of /var/log/messages when it happens:

    Jul 18 22:25:46 lumpy kernel: acd0: WARNING - TEST_UNIT_READY
taskqueue timeout - completing request directly
    Jul 18 22:26:25 lumpy kernel: acd0: FAILURE - device detached
    Jul 18 22:26:25 lumpy kernel: acd0: WARNING - TEST_UNIT_READY
freeing taskqueue zombie request

This is straight-up 7.2-RELEASE amd64, with current port of audio/ripit.
I can mount/umount the cdrom and read a normal data disk with no
issues. FWIW, the drive shows up in dmesg like this:
    acd0: CDRW <LITE-ON LTR-24102B/5S07> at ata0-slave UDMA33

Any ideas what is going on or how to fix it?
It is nicely repeatable, at least.

-John