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Date:      Sat, 7 Oct 1995 20:29:18 +0100
From:      se@zpr.uni-koeln.de (Stefan Esser)
To:        -Vince- <vince@apollo.cosc.gov>
Cc:        hackers@freebsd.org
Subject:   Re: machine reboot & kernel maxusers option
Message-ID:  <199510071929.AA11276@Sysiphos>
In-Reply-To: -Vince- <vince@apollo.COSC.GOV> "machine reboot & kernel maxusers option" (Oct  7,  4:45)

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On Oct 7,  4:45, -Vince- wrote:
} Subject: machine reboot & kernel maxusers option
} Hi everyone,
} 
} 	I am experiencing the following problem and the machine just 
} reboots under FreeBSD-current, anyone have any ideas?

There have been no functional changes to the driver
for nearly a month now ...

Did you rebuild your kernel within that time ?

} MAND FAILED (4 28) @f0b4aa00.
} assertion "cp" failed: file "../../pci/ncr.c", line 5560
} sd0(ncr0:0:0): COMMAND FAILED (4 28) @f0b4aa00.

Hmm, the 28 in the message above means "Queue Full", i.e.
there were too many commands issued by the generic SCSI
driver. But the maximum number of commands to issue is a
parameter known to the generic SCSI code, so this should
never happen ...


In fact, there was a change one month ago, which did change
the size of the command queue. But in fact, the queue size 
was increased ...

You may want to try changing back the line (ncr.c:132):

#define MAX_START   (MAX_TARGET + 7 * SCSI_NCR_MAX_TAGS)

into its previous form:

#define MAX_START   (7 * SCSI_NCR_MAX_TAGS)


I'll look into this, but I need more information:

1) Complete verbose boot message log, if possible
   (I.e. Boot with "-v" option, send "/sbin/dmesg" output).

2) When does this happen ?
   At boot time, or when the system had been heavily loaded ?
   Which devices are connected ? active ?

There is a timeout function in the driver, which should 
reset the NCR chip after some 10 seconds of no progress
on any outstanding command.

This ought to clear the error condition ...


} 	Also, can someone tell me what the maxusers option in the kernel 
} config file does exactly?  Thanks!

Look for uses of MAXUSERS in "/sys/conf/param.c".


Regards, STefan

-- 
 Stefan Esser, Zentrum fuer Paralleles Rechnen		Tel:	+49 221 4706021
 Universitaet zu Koeln, Weyertal 80, 50931 Koeln	FAX:	+49 221 4705160
 ==============================================================================
 http://www.zpr.uni-koeln.de/staff/esser/esser.html	  <se@ZPR.Uni-Koeln.DE>



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