[1242] in linux-scsi channel archive
Re: AHA2742T - switch channels (Linux) ?
daemon@ATHENA.MIT.EDU (Steffen Grunewald)
Thu Jan 9 03:26:35 1997
From: Steffen Grunewald <steffen@gfz-potsdam.de>
To: deischen@iworks.InterWorks.org (Daniel M. Eischen)
Date: Thu, 9 Jan 1997 09:22:23 +0100 (MET)
Cc: aic7xxx@FreeBSD.ORG, linux-scsi@vger.rutgers.edu
In-Reply-To: <9701081638.AA29959@iworks.InterWorks.org> from "Daniel M. Eischen" at Jan 8, 97 10:38:56 am
Answering my question on aic7xxx@freebsd.org, Daniel M. Eischen writes:
|>
|> > Is it possible to switch the channels (according to the EISA settings)
|> > of the two channels A and B of an Adaptec 2742 Twin ?
|> > Under DO$, it's possible. Unfortunately the aic7xxx driver in 2.0.18
|> > (which is what I currently use) doesn't support that EISA setting.
|> > Is there any work being or having been done since the days of 2.0.18 ?
|>
|> The Linux driver can determince which channel is primary, but it can't
|> change the order of channel probing, and thus device detection and
|> assignment. This will be solved in future mid-level SCSI code
|> changes, not driver changes. Talk to the linux-scsi mailing
|> list if you want to ask questions about future changes to the
|> Linux scsi code.
|>
|> You can, for now, hack the mid-level SCSI code (linux/drivers/scsi/scsi.c)
|> to force the channels to be probed in reverse order. In function
|> scan_scsis(), change:
|>
[patch reversing the host order]
|>
|> This will probe devices on channel B first.
Well, that's o.k.as long as there are no other hosts in the system, the
order of which also would be reversed. IMHO, the necessary changes should
be done in the low-level code (as there we can determine whether the BIOS
swapping of the channels is in effect) - perhaps by re-ordering the make
of the entries in the host list ?
--
Steffen Grunewald | email steffen@gfz-potsdam.de | fax (+49)-331-8877 520
<A HREF="http://www.gfz-potsdam.de/">GeoForschungsZentrum Potsdam</A>
Telegrafenberg A17, D-14473 Potsdam, Germany
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