Subject: port-hp300/460: scsi slaves treated as unit's
To: None <gnats-admin>
From: Jason R. Thorpe <thorpej@mail.CS.ORST.EDU>
Date: 09/05/1994 13:20:20
>Synopsis: scsi slaves treated as unit's
>Responsible: gnats-admin (GNATS administrator)
>Arrival-Date: Mon Sep 5 13:20:19 1994
>Originator: Jason R. Thorpe
Department of Computer Science
Oregon State University
>Release: NetBSD 1.0_BETA (sup'd 9/4/94)
System: NetBSD santiam 1.0_BETA NetBSD 1.0_BETA (SANTIAM) #0: Thu Aug 11 13:42:08 PDT 1994 thorpej@santiam:/tmp_mnt/hurricane/NetBSD/src/sys/arch/hp300/compile/SANTIAM hp300
When attempting to place root and swap on a device other than
slave 0, autoconf.c generates a warning:
WARNING: using device at unit 0 of controller
This is due to scsi being fundamentally different
from hpib. hpib drives have 1 controller per disk, whereas
many drives hang off of a scsi controller. These drives
hanging off of the controller are being incorrectly treated
as units, similar to the hp7946 (which has a disk at unit 0
and a tape at unit 1). The code always assumes unit 0, which
in the case of scsi, is not necessarily correct.
bits from my kernel config:
config netbsd root on sd0 swap on sd0b
master scsi0 at scode?
master scsi1 at scode?
master scsi2 at scode?
master scsi3 at scode?
disk sd0 at scsi0 slave 5
disk sd1 at scsi0 slave 6
disk sd2 at scsi0 slave 2
disk sd3 at scsi0 slave 3
disk sd4 at scsi0 slave 4
disk sd5 at scsi0 slave 5
disk sd6 at scsi0 slave 6
disk sd7 at scsi1 slave 0
disk sd8 at scsi1 slave 1
disk sd9 at scsi1 slave 2
disk sd10 at scsi0 slave 0
tape st0 at scsi? slave ?
tape st1 at scsi? slave ?
Note that scsi0, slave 0 is a cdrom drive...
Upon booting a kernel configured in this manner, after the autoconf
sequence, the warning message is generated and the kernel reports:
changing root device to sd10a
...and then panics with a zero-divide trap, because the drive is
empty. This behavior is not exihibited if booting off of an hpib
disk, no matter which slave, since the disk is always at unit 0 (at
least it is on all of my hpib disks...)
Note - just umplugging the cdrom won't do it, since sd0 is still at
slave (and therefore unit) 5 of scsi0
Well, I can describe how I'd do it...
Determine whether or not the root/swap is being done
on a scsi disk. If so, then set the unit # check to
the slave id, and also use that number whenever unit 0
is assumed. If the disk is not scsi, then perhaps just
default to unit 0, as the code does now. Essentially, the following
(at line 1024 of autoconf.c) is incorrect:
if (unit != 0)
printf("WARNING: using device at unit 0 of controller\n");
mindev = hd->hp_unit;
Actual code is unknown to me at the moment...But after enough
coffee, I'm sure I can come up with something...