wd0 at atabus5 no longer found

[Roy Marples <roy%marples.name@localhost>]

Hi List

Trying to upgrade my kernel from Feb 12 to now fails as it no longer
finds my disk. Kernel configs are identical for me.
Here's the dmesg snippet from the working kernel

uberpc$ dmesg | grep wd0
wd0 at atabus5 drive 0: <WDC WD5000AAKS-22YGA0>
wd0: drive supports 16-sector PIO transfers, LBA48 addressing
wd0: 465 GB, 969021 cyl, 16 head, 63 sec, 512 bytes/sect x 976773168
sectors
wd0: drive supports PIO mode 4, DMA mode 2, Ultra-DMA mode 6 (Ultra/133)
wd0(ahcisata1:1:0): using PIO mode 4, DMA mode 2, Ultra-DMA mode 6
(Ultra/133) (using DMA)

Any clues as to why this is no longer working? I'm using an ABIT IP35
Pro motherboard with the latest BIOS update.

Thanks

Roy