PCI excessive retry error

PCI excessive retry error

[Shobhit Mathur]

Hello,

I have a situation in which sending ioctls from a user
application to an HBA at the same time as active I/Os
running on the same card causes a critical error as - 
PCI excessive retry error.

I would like to know what can be the causes of such a
problem and what type of solution can resolve such 
problems.....?

- Thank you



	
		
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Re: PCI excessive retry error

[Richard B. Johnson]

On Mon, 10 May 2004, Shobhit Mathur wrote:

> Hello,
>
> I have a situation in which sending ioctls from a user
> application to an HBA at the same time as active I/Os
> running on the same card causes a critical error as -
> PCI excessive retry error.
>
> I would like to know what can be the causes of such a
> problem and what type of solution can resolve such
> problems.....?
>
> - Thank you
>

How do you know? The PCI/Bus transparently retries. What
facillity reports the error?  In any event, if the PCI/Bus
hasn't been destroyed, the problem is caused by the failure
of some driver to set the cache-line size and/or the
latency timer. For ix86 machines the cache-line size
is "8" (8 longwords). Some software may mistakenly
set it to 32 because the author didn't understand the
documentation. A latency timer of 64 or lower, and a
cache-line size of 8 should solve your problems. These
problems don't show up unless the PCI device is a bus-master.

I mentioned a "broken bus" in the beginning. Some new
PCI boards are not 5-volt tolerant. If you plug them into
the PCI bus of some motherboards (Intel 865PE chipset),
The Intel D865PERL, for one, the PCI/Bus will get blown.
Same with the MS-6585 (648 MAX board). I blew up several
boards by plugging 3.5 volt PCI cards into the 5 volt
bus. According to the rules, it's supposed to work unless
the PCI slots have "Cadium Yellow" or "Brilliant Blue"
keying plugs (I kid you not, it's in the PCI specs).

Anyway, you get to eat a few US$150 boards if you are not
careful.

Cheers,
Dick Johnson
Penguin : Linux version 2.4.26 on an i686 machine (5557.45 BogoMips).
            Note 96.31% of all statistics are fiction.

Re: PCI excessive retry error

[John Bradford]

> I mentioned a "broken bus" in the beginning. Some new
> PCI boards are not 5-volt tolerant. If you plug them into
> the PCI bus of some motherboards (Intel 865PE chipset),
> The Intel D865PERL, for one, the PCI/Bus will get blown.
> Same with the MS-6585 (648 MAX board). I blew up several
> boards by plugging 3.5 volt PCI cards into the 5 volt
> bus. According to the rules, it's supposed to work unless
> the PCI slots have "Cadium Yellow" or "Brilliant Blue"
> keying plugs (I kid you not, it's in the PCI specs).

So, did you actually plug the cards in to the wrong coloured slots, or
do you have a 3.5 volt-incompatible motherboard with a colour of slots
which suggests compatibility?

John.

Re: PCI excessive retry error

[Richard B. Johnson]

On Mon, 10 May 2004, John Bradford wrote:

> > I mentioned a "broken bus" in the beginning. Some new
> > PCI boards are not 5-volt tolerant. If you plug them into
> > the PCI bus of some motherboards (Intel 865PE chipset),
> > The Intel D865PERL, for one, the PCI/Bus will get blown.
> > Same with the MS-6585 (648 MAX board). I blew up several
> > boards by plugging 3.5 volt PCI cards into the 5 volt
> > bus. According to the rules, it's supposed to work unless
> > the PCI slots have "Cadium Yellow" or "Brilliant Blue"
> > keying plugs (I kid you not, it's in the PCI specs).
>
> So, did you actually plug the cards in to the wrong coloured slots, or
> do you have a 3.5 volt-incompatible motherboard with a colour of slots
> which suggests compatibility?
>
> John.
>

I have two broken motherboards that have off-white color slots
that imply that they should certainly not blow up if anything
that fits is plugged into them!

So I plugged in two high-speed data-link boards and nothing worked.
Upon removal of the boards, my SCSI controller was no longer seen
on the PCI/Bus. I called the data-link board vendor (actually a
division of this company) and they said; "Idiot! They are 3.5 volt
boards!". I said; "Yeh? The PCI Spec says they should be compatible!"
They said; "There is no PCI spec for such compatibility......", etc.
etc. When I quoted the page on the book, they said; "That's only a
BOOK, not a specification...." It's just like the l-k list.

So, some new PCI/Bus boards are not 5-volt tolerant. Some new
board slots run at 3.5 volts so older PCI/Bus boards won't
work (some do, some don't). It's a mess.

I also asked our wizards in the other division what kind of
platform the boards were supposed to be working in. They said
it was secret, but not a PC.

Cheers,
Dick Johnson
Penguin : Linux version 2.4.26 on an i686 machine (5557.45 BogoMips).
            Note 96.31% of all statistics are fiction.