2.4 ICH4 + SATA bridge problems

From: Rumi Szabolcs
Date: Thu Nov 06 2003 - 19:41:26 EST


I've got here an i845PE-based motherboard with the usual
Marvell 88i8030 PATA->SATA bridge chip. When I connect a
SATA drive to this one, the BIOS recognizes it as an UDMA100
device, but the kernel (2.4.22) only uses UDMA33, and hdparm
also only reports support up to udma2, which results in a
performance of about 15MB/sec (hdparm -t) vs. the >50MB/sec
these drives can normally push.

I have tested this with two different drives, a fully native
SATA drive (ST3160023AS) and a pseudo-SATA drive (MX6Y120M0)
which uses the same Marvell chip internally to convert SATA
back to PATA because thats what the drive really is. The
result is that both drives show up as UDMA100 in the BIOS
and as UDMA33 in the kernel.

What is the reason for this?
Any comments/fixes out there already?


Szabolcs Rumi
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