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From: obrien@cs.ucdavis.edu (David E. O'Brien)
Message-Id: <9601041020.AA14216@toadflax.cs.ucdavis.edu>
Subject: SCSI bus/device timeouts on AHA-1542b
To: freebsd-questions@freebsd.org
Date: Thu, 4 Jan 1996 02:20:32 -0800 (PST)
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I've a got a problem with every SCSI hard drive I've hooked up to my
Adaptec AHA-1542b controler.  I newfs the drive ok.  (disk label reports 

After hard useage (heavy cp'ing/tar'ing), I get:

Jan  3 02:56:35 foobar /kernel: sd0(aha0:0:0): timed out
Jan  3 02:56:35 foobar /kernel: adapter not taking commands.. frozen?!
Jan  3 02:56:35 foobar /kernel: sd0(aha0:0:0): timed out
Jan  3 02:56:35 foobar /kernel: adapter not taking commands.. frozen?!
Jan  3 02:56:35 foobar /kernel: Debugger("aha1542") called.
Jan  3 02:56:35 foobar /kernel: Debugger("aha1542") called.
Jan  3 02:56:35 foobar /kernel:  AGAIN
Jan  3 02:56:35 foobar /kernel:  AGAIN
Jan  3 02:56:35 foobar /kernel: aha0: MBO 02 and not 00 (free)
Jan  3 02:56:35 foobar /kernel: aha0: MBO 02 and not 00 (free)
Jan  3 02:56:45 foobar /kernel: sd0(aha0:0:0): timed out
Jan  3 02:56:45 foobar /kernel: adapter not taking commands.. frozen?!
Jan  3 02:56:45 foobar /kernel: Debugger("aha1542") called.

I get simlar messages on the console and all SCSI devices hang.  As does
rebooting.

What is the "Debugger("aha1542") called"?  What do I do with it (if it
ever pops up)?

Any ideas how to investigate?  Can I somehow bump up the timeout values
in the kernel, or set the kernel to not pound so hard on the SCSI bus?

More details:  Running FreeBSD 2.1.0-R, SCSI disk is Micropolis 1588-15
and is SCSI-1.  The same happens with an old Seagate ST-2383N SCSI-1
drive.  Under FreeBSD 2.0.5-R I could newfs the SCSI drives, but any
accesses would cause a kernel panic.  Also on the scsi bus is a Pioneer
DRM-604x CDROM changer (which FreeBSD supports perfectly!).  My main
drive is my second W.D. EIDE drive (with the first W.D. IDE drive for MS
crap OS's).  Sometimes I also have an Exebyte 8505 8mm tape drive on the
same SCSI bus.

In fact when tar'ing files to the Exebyte drive, I often get:

    tar: can't write to /dev/rst0 : Input/output error
    Dec 28 14:36:37 foobar /kernel: st0(aha0:4:0): timed out
    Dec 28 14:36:37 foobar /kernel: st0(aha0:4:0): timed out       

-- David   (obrien@cs.ucdavis.edu)