boot hang: "ata1: resetting devices .. done" (5.1-CURRENT, IBM T30)

[Robert Ferguson]

I see this problem as well. I'm running on a T40, with a DVD/CDRW in  
the ultrabay, and -CURRENT as of this morning. At boot, it hangs  
immediately after

ad0: 35174MB <IC25N040ATCS05-0> [71465/16/63] at ata0-master UDMA100
ata1: resetting devices ..
done

Backing out the most recent checkin to sys/dev/ata/ata-queue.c (i.e.  
reverting to version 1.6) makes the problem go away.

A verbose dmesg from the machine (with that change removed) can be  
found at http://www.fergusonlabs.com/t40/dmesg0.txt

Thanks,
Rob Ferguson