Subject: Re: scsipi hardware driver to midlayer: how to signal bus timeout?
To: Ignatios Souvatzis <is@jocelyn.rhein.de>
From: Michael L. Hitch <osymh@terra.oscs.montana.edu>
List: tech-kern
Date: 11/01/1999 10:50:01
On Mon, 1 Nov 1999, Ignatios Souvatzis wrote:

> Can a sbic chip tell the difference between a busy bus and no device
> responding? (I have a sbic manual somewhere, but... "somewhere")

  Ugh - it's been a long time since I've looked at that driver.  I don't
know offhand about that, and I don't know where my 33c93 documention is
at the moment either (at least I think I have some... "someplace").  The
select routine does check to see if the chip is already selected, and also
checks to see if it got reselected.  Both cases return the same value as
it does on a selection timeout.

  Ah - the caller of sbicselectbus() can check dev->sc_xs->error for the
timeout error code when sbicselectbus() signals a selection failure.

> Related question: Michael, and advice on whether sci.c should work, or needs
> changes, too? (I could guess from the source, but you, at least, have once
> written a sci backend...)

  It's been even longer since I looked at that driver :-)

  A quick perusal of the driver looks like it terminates the command if
sciselectbus() fails.  Since that driver doesn't do disconnects, it will
never have to worry about reselects taking control and assumes any
selection failure is a non-resposive target.

--
Michael L. Hitch			mhitch@montana.edu
Computer Consultant
Information Technology Center
Montana State University	Bozeman, MT	USA