Subject: Re: UDMA errors with Promise in Miata
To: David Hopper <dhop@nwlink.com>
From: Michael Kukat <michael@unixiron.org>
List: port-alpha
Date: 03/31/2005 14:30:38
Hi,


On Wed, 30 Mar 2005, David Hopper wrote:
> Hmm...  I had wondered if this was fixed by now.  I had this exact
> error some two years ago with a Promise Ultra133TX2 controller.  My
> solution was to drop down to an Ultra/66 controller.  I've had success
> with both SIIG and Promise Ultra/66, but this Promise 133TX2 has been
> gathering dust until I can verify that it works...  :(

Okay, i hardwired the 2 drives at the Promise to UDMA3 now, works like a charm:
bash-2.05b# dd if=/dev/rwd1c bs=1m count=1024 of=/dev/null
1024+0 records in
1024+0 records out
1073741824 bytes transferred in 27.598 secs (38906508 bytes/sec)
bash-2.05b# dd if=/dev/rwd2c bs=1m count=1024 of=/dev/null
1024+0 records in
1024+0 records out

It's not max performance what to get out of those drives i think, but it's okay
for a workstation :) I had a look into the source and tried to compare them
with a path promise sent for linux a while ago for the 133TX2. Currently, i
didn't see parallelities because of the very different implementation of the
programming of timing relevant registers. And i have to dive into this a bit
deeper to understand this kind-of-sick UDMA stuff a bit more. For my
understanding, UDMA2 can use the standard 40pin cables, UDMA4 needs the 80wire
40pin cables, but UDMA3 (44MB/s?) doesn't seem to have a real
standard/recommendation about this.
BTW... I also tried UDMA4 with the promise thingies, and it really was no
success. But for now it works.

I've seen some other strangeness today:

If i connect a CD-ROM to the primary onboard IDE channel, the secondary channel
is disabled by the firmware. If a hard disk is connected to pri, sec is
enabled. Does anyone know a workaround for this? I have something in mind, that
the second channel of the onboard CMD isn't capable of DMA, which is needed for
the DVD writer, while i'm booting off a flash module, which just knows about
PIO4.

...Michael

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