[coreboot] is multi-mode important in sata/ide land, and in particular on ck804?

[Ward Vandewege]

Now that I've got all sata ports working on the s2891, bonnie++ tells me that
the disks are much slower under coreboot than under the proprietary bios.
Compare

http://ward.vandewege.net/coreboot/s2891/s2891-20080421-cb-bonnie++

and

http://ward.vandewege.net/coreboot/s2891/s2891-20080421-prop-bonnie++

Under the proprietary bios bonnie++ is about twice as fast as under coreboot.

When comparing hdparm output, I found that under coreboot none of the drives
have multi mode enabled.

coreboot:

[    0.000000] ata3.00: 488397168 sectors, multi 0: LBA48

proprietary:

[   54.523384] ata3.00: 488397168 sectors, multi 16: LBA48

(full dmesg, hdparm, etc available at
http://ward.vandewege.net/coreboot/s2891/).

The hdparm output also shows that -t and -T values are more or less
comparable under coreboot and the proprietary bios. Caching?

Looking at other machines running coreboot (mostly mcp55 based), it seems
that none of the drives in them have multi mode enabled.

Uwe did some testing on a board with a non-nvidia chipset, and found that
multi mode was not enabled under coreboot there either, but it did not affect
his performance numbers.

So - is multi mode important when doing dma? Is it important on ck804 only?
Does it matter on other chipsets? Any other ideas of what could be affecting
the performance numbers I get on the s2891?

Thanks,
Ward.