[132] in linux-scsi channel archive
Re: Dangerous bug in generic scsi device
daemon@ATHENA.MIT.EDU (Drew Eckhardt)
Thu Apr 6 08:34:58 1995
To: svedja@lysator.liu.se
cc: submit-linux-dev-scsi@ratatosk.yggdrasil.com, entropy@world.std.com,
heiko@colossus.escape.de
In-reply-to: Your message of "Sat, 01 Apr 1995 21:32:20 +0200."
<Pine.LNX.3.91.950401213000.113A-100000@Morgaine.rydnet.lysator.liu.se>
Date: Thu, 06 Apr 1995 04:32:55 MDT
From: Drew Eckhardt <drew@boulder.openware.com>
In message <Pine.LNX.3.91.950401213000.113A-100000@Morgaine.rydnet.lysator.liu.
se>, svedja@Morgaine.rydnet.lysator.liu.se writes:
>Hi, I've allready sent a copy to entropy@world.std.com,
>heiko@colossus.escape.de
>
>Here comes the letter:
>Hi.
> Thanks for a wonderful system. Without it my development of software for
>a non-standard 3M scsi tape streames would be impossible.
>
>Now about the bug:
>
> Someone tell me if it is a bug or not but according to the HOWTO &
>logical sense it is.
It's not a bug. The HOWTO states in a number of places
"minor numbers are assigned dynamically starting with the lowest
SCSI HOST/ID/LUN"
which implies SCSI HOST is considered first, ID next, LUN last.
>If you have (like me) 2 units attached to one controller everyting is OK.
>If you have 2 controllers with one unit each, the unit with HIGHER lun on
>controller that detects first, the bug will show up by reversing the
>order of my units!!! sga <--> sgb !!
First off, you're not talking about LUNs. You're talking about
SCSI IDs. There's a difference.
>
>my config 1 (OK):
>
>NCR-810 controller (PCI)
> MAXTOR 340MB (lun 1) disk
> 3M MCD-II/SCSI (lun5) tape
>
>sga --> MAXTOR { OK }
>sgb --> 3M { OK }
This is as expected : on each SCSI controller, lower numbered
targets are probed first.
>config where the bug shows up: (in order of detecting by system)
>Future Domain 1680 (ISA) controller with 3M tape
>NCR-801 controller MAXTOR 340 disk.
>
>sga --> 3M { BAD }
>sgb --> MAXTOR { BAD }
This is also as expected. As documented in the SCSI-HOWTO,
Section 3.1.1 : Multiple host adapters
SCSI controllers are scanned in the order specified in the
builtin_scsi_hosts[] array in drivers/scsi/hosts.c, with
the order currently being
Ultrastor, Adaptec 151x/152x, Buslogic, Adaptec 154x,
Adaptec 174x, Future Domain 16x0, Allways IN2000, Generic
NCR5380, PAS16, Seagate, Trantor T128/T130, NCR53c8xx,
EATA-DMA, WD7000, debugging driver.
Ie, all targets on scsi0 (in your case, the future domain
board) are probed before all targets on scsi1 (in your case,
the NCR board).
