[3881] in linux-scsi channel archive
Re: changing host ID of ncr53c810?
daemon@ATHENA.MIT.EDU (Gerard Roudier)
Sat May 9 16:44:37 1998
Date: Sat, 9 May 1998 21:48:54 +0200 (MET DST)
From: Gerard Roudier <groudier@club-internet.fr>
To: Richard Waltham <dormouse@farsrobt.demon.co.uk>,
Dan Hollis <goemon@sasami.anime.net>
cc: linux-scsi@vger.rutgers.edu
In-Reply-To: <199805081947.UAA05480@farsrobt.demon.co.uk>
On Fri, 8 May 1998, Richard Waltham wrote:
> Dan Hollis wrote:
> >
> > Is it possible to change the hostID of a 53c810 to something other than 7?
> > The cards dont have nvram.
> >
>
> Yes. You need to patch the SCSI driver on one of the systems to change the
> default ID. For the ncr53c8xx (ncrBsd2Linux) driver the following should
> patch most versions without problems.
>
> -----------8<-----------------------
> --- linux-2.0.34/drivers/scsi/ncr53c8xx.c~ Fri May 8 20:25:34 1998
> +++ linux/drivers/scsi/ncr53c8xx.c Fri May 8 20:25:34 1998
> @@ -323,7 +323,7 @@
> */
>
> #ifndef SCSI_NCR_MYADDR
> -#define SCSI_NCR_MYADDR (7)
> +#define SCSI_NCR_MYADDR (6)
> #endif
>
> /*
> -----------8<-----------------------
Using (6) is ok, since it is recommended that initiators have the
highest priority on the BUS in order to send commands to devices
as quickly as possible.
But this patch is probably not enough, since the driver does not overwrite
the host-id if it is not zero. The following should also be patched if
you are using the SDMS BIOS with your 810, or are booting from an O/S that
initialized the controller:
/*
** Get SCSI addr of host adapter (set by bios?).
*/
+ #if SCSI_NCR_MYADDR == (7)
if (!np->myaddr) np->myaddr = INB(nc_scid) & 0x07;
if (!np->myaddr) np->myaddr = SCSI_NCR_MYADDR;
+ #else
np->myaddr = SCSI_NCR_MYADDR;
+ #endif
(Note that all the controllers driven by the hacked driver version will
use hard-coded host-id 6).
> > Trying to run shared scsi bus between 2 computers, to share a tape drive
> > and cdrom. The two hostadaptors are going to need to use different host
> > IDs.
> >
> > -Dan
> >
>
> Apart from the host ID there are other problems that could occur but thats
> another story. But you should be ok if you only access the drives from one
> system at a time.
Probably. But you have to be aware that the both systems will reset the
SCSI BUS at linux start-up, at least ...
> Bye for now
> Richard
Regards,
Gerard.
-
To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
the body of a message to majordomo@vger.rutgers.edu
