UDMA4

Hello,

Just wondering if anyone has any tips for enabling UDMA5.

I am currently using a 40GB WD disk that supports ATA100.
This is under Fedora Core 1 with a ECS K7A5Spro mainboard.  The SIS735
chipset, which this board uses, is supposed to support ATA100, but I can't
seem to get it working.

When I check the udma transfer mode using hdparm here is what I get:

[root@squirt root]# hdparm -i /dev/hda | grep udma
UDMA modes: udma0 udma1 udma2 udma3 *udma4 udma5

UDMA4 is currently the default transfer mode, but I want UDMA5.

I can enable it - be it briefly - by passing the -X69 switch to hdparm:

[root@squirt root]# hdparm -X69 /dev/hda
/dev/hda:
setting xfermode to 69 (UltraDMA mode5)

Yet no matter what, a few seconds later it will reset to UDMA4.

I have tried to add the -X69 to /etc/sysconfig/harddisks, but it still
resets to UDMA4.

[root@squirt root]# cat /etc/sysconfig/harddisks | grep X69
EXTRA_PARAMS=-X69

Any suggestions?  I doubt I would see much of a performance boost anyway,
but just in case.

Thanks

Brian