This patch addresses a bug in the ASIC on the 6400 series controllers. When
prefetching from host memory we grab an extra 750 or so bytes of data. If
this occurs on a memory boundary the machine will MCA. This bug affects IPF
and Alpha based platforms. It is not known to be a problem on x86.
Prefetch will be disabled via the f/w. We need to enable it on x86 to
address a _big_ performance hit on RAID 1 operations.