Subject: Re: Narrowing a wide scsi bus
To: Chris Ross <cross+netbsd@distal.com>
From: Christian Smith <csmith@micromuse.com>
List: current-users
Date: 09/14/2004 18:22:08
On Tue, 14 Sep 2004, Chris Ross wrote:

>
>   Hi there.  I have a machine (sparc64) which has a wide scsi controller
>in it, and a wide SCSI disk, but only a narrow scsi cable.  The cases for
>this are difficult to explain, but the disk has a receiver, so I can't
>simply put a wide cable in.


What do you mean by a receiver? Do you mean a caddy, plugging into a
backplane?


>
>   Is there a way to tell NetBSD, when booting, to treat a scsibus as
>narrow, and all the devices on it as narrow, regardless of what they
>otherwise negotiate?  I looked in docs and on the web, and was unable to
>find this.
>
>   Any suggestions?


Narrowness or wideness is a property of the physical SCSI bus itself, not
of the driver. AFAIK, the only kernel level difference will be that the
scsibusX attached to the driver will have a maximum of 8 devices (inc.
controller.) A quick scan through esp_sbus.c, for example, only brings up
a through special cases for the FAS366 wide SCSI controller over the older
ESP[12]00 narrow chips, and none of those look like narrow/wide
specialisations.

Does NetBSD not see the disk? From the prom, what does probe-scsi or
probe-scsi-all output? Make sure the drive has an ID<7.

FWIW, I have wide SCSI devices plugged into a narrow bus with no problems
using ESP200 SBUS based controller.


>
>   Thanks...
>
>                                - Chris
>

Christian

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