RELENG_6 SATA drive error

[Michael C. Shultz]

I have one IDE and two SATA drives in my system.  With
FreeBSD 5.4 the system would not boot from the SATA
drive so I use the IDE as the primary then mount
the SATA drives in fstab.  I tried upgrading to RELENG_6
and with the new kernel one of the SATA drives errors
out and so can't be mounted.  I don't have the error message
using the 6.0 kernel but here is dmesg from 5.4 if it helps:

ad4: 76319MB <WDC WD800JD-00HKA0/13.03G13> [155061/16/63] at ata2-master 
SATA150
ad6: 114473MB <WDC WD1200JD-00HBB0/08.02D08> [232581/16/63] at ata3-master 
SATA150

It is at4 that is failing with 6.0, this drive never gives any problem under 
5.4.  Both SATA drives are plugged into the same really cheap addon pci
card.

I'll be happy to provide more detail if requested and I'm able.

Thank you,

-Mike