Affected chipsets support LBA48 but not LBA48 DMA.
Just use DMA for area < 137GB and revert to PIO for > 137GB one.
Also disallow transfers > 256 sectors for better performance.
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@elka.pw.edu.pl>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>