landisk DMA broken in NetBSD 6

Hi,

After upgrading aPlextor PX-EH25L to NetBSD 6, I noticed that the machine would 
crash after a few hours of use and an fsck on another machine would show all 
sorts of issues. I think the DMA problem never got fixed. After compiling a 
NetBSD 6 kernel with DMA modes disabled, it seems fine:

wd0 at atabus0 drive 0
wd0: <HDT722525DLAT80>
wd0: drive supports 16-sector PIO transfers, LBA48 addressing
wd0: 232 GB, 484521 cyl, 16 head, 63 sec, 512 bytes/sect x 488397168 sectors
wd0: 32-bit data port
wd0: drive supports PIO mode 4, DMA mode 2, Ultra-DMA mode 6 (Ultra/133)
wd0(acardide0:0:0): using PIO mode 4

Doing a full cvs update of pkgsrc, then an fsck showed no problems.

Does anyone have a clue about how best to fix this?

Thanks,
John Klos