2940UW problems.

[James O'Kane]

On Mon, 21 Jun 1999 dledford at redhat.com wrote:
> The Max Active SCBs is not a limit, it's an actual count.  This is the most
> SCBs that the system has had active at one time.  This would imply that you
> don't have tagged command queueing enabled on your drives or else this number
> would be much higher.  Anyway, that's not the problem.  In your case it sounds
> like the bus is underterminated (aka, you have termination enabled at one end
> of the bus or the other, but not both like it should be).  That will commonly
> cause the parity problems that result in the busfree conditions you are
> seeing.


So we took your suggestion and checked the termination, while it claimed
it was terminating the bus automatically, I turned off the auto
termination and turn it on explicitly. This seemed to do the trick and the
drives worked happily for a week against everything I threw at them. We
then tried to move the drives to their real home, on another machine and
it blew up within 4 hours with a kernel panic similar to what we were
seeing before. We've come up with a list of things that were changed
between the two machines in hopes that one would help determine what the
problem could be.
 
Working machine:              Non-working machine:

Dual PII                      Dual PPro

(1) PCI 2940UW, (1) onboard   (2) PCI 2940UW
294x card.

440LX chipset                 440FX chipset

256M in DIMMS                 256M in EDO SIMMS

BIOS loaded                   BIOS not loaded


These drives in question are one what I'm going to call the second card
in the non-working machine. On the first card there are two drives.
I had to turn off the loading of the BIOS on the non-working machine
because of the way that the SCSI names were being assigned, the root
partition was not on sda as expected. If I turned off the BIOS on the
second card, it would assign drive names to the first card first.

Both machines are using the same 2.2.6 kernels with the same patches. Is
there any other information that would help diagnose this?

thanks
-james




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