Re: 2.8 sees hard drive; 3.0 doesn't

[Nick Holland <nick@holland-consulting.net>]

Ben Goren wrote:

> On one  of them, none  of the  3.0 install floppies  recognize the
> hard drive. On the other, all is fine. I've tried all three images
> on the  CD, plus the  floppy30.fs from  the latest snapshot  and a
> ``make  release''  of -stable  done  on  the  28th; if  there's  a
> different result among the five disks, I can't see it.
> 
> Suggestions most welcome; dmesges below.

I love dmesg's, thanks! 8-)

This is not an authoritative answer, more of a guess, but I think I
can help you get the thing back up and running.

My guess as to what is going on:

The one that is not working is running an old ST3290A (that would be a
250M IDE drive), which is not a DMA drive (no, I don't have this
memorized...but I think the age and size would make this a good
guess), whereas the one that works is a Western Digital AC2850F, an
850M drive, right about the time WD started doing DMA drives (this is
from memory.  DON'T quote me as an authority on this! 8-) and the 3.0
driver detects it as DMA mode 1 (and PIO mode 0, which I believe is
pretty ugly...).  

So, either the PCIIDE driver of 3.0 doesn't recognize old drives, or
that driver on that chipset on with that drive aren't working
together.  Interestingly, I don't think I've ever tried to put a very
old drive on a not-so-old computer, so I'm not sure how wide-spread
this problem would be...

If you want to prove me wrong (or right), swap the drives between the
machines, the problem should follow the drive, not the machine.

I'm guessing if you were to disable the pciide driver (which forces
the system to use the older non-DMA driver), it will recognize the
ST3290A drive.  This can be done by doing this:

boot> boot -c
<bla, bla, bla>
ukc> disable pciide*
pciide* disabled
ukc> quit
<resumption of boot>

You can then use config(8) to make this change permanent or build your
own kernel without pciide.

There were a lot of enhancements of the PCIIDE driver since 2.8,
something may have broke support of that drive on that chip.

Yeah, disabling DMA support hurts performance, but shouldn't have much
impact on a firewall...besides, you weren't getting DMA before on that
machine (and if the non-pciide driver does better than PIO 0, you
might gain).

Nick.
-- 
http://www.holland-consulting.net