>Number:         2156
>Category:       kern
>Synopsis:       time outs of Exabytes
>Confidential:   no
>Severity:       critical
>Priority:       medium
>Responsible:    kern-bug-people (Kernel Bug People)
>State:          open
>Class:          change-request
>Submitter-Id:   net
>Arrival-Date:   Fri Mar  1 15:50:02 1996
>Last-Modified:
>Originator:     Klaus Helbing
>Organization:
Physikalisches Institut Uni Bonn
>Release:        NetBSD-current Feb 7
>Environment:
System: NetBSD phop5.physik.uni-bonn.de 1.1A NetBSD 1.1A (PHOP) #0: Wed Feb 7 15:50:38 MET 1996 helbing@phop5.physik.uni-bonn.de:/usr/src/sys/arch/i386/compile/PHOP i386


>Description:
	NetBSD crashes every once in a while during write to Exabyte-Tape.
	I tried to find out what happens and compiled /sys/scsi/st.c with
	-DSCSIDEBUG into the kernel. The last lines before the crash in 
	/var/log/messages look the following:
Feb 29 15:39:40 phop5 /netbsd: st0(ahc0:4:0): ststart 
Feb 29 15:39:40 phop5 /netbsd: st0(ahc0:4:0): ststart st0(ahc0:4:0): ststrategy 65536 bytes @ blk 1613440
Feb 29 15:39:40 phop5 /netbsd: st0(ahc0:4:0): ststart st0(ahc0:4:0): ststart 
Feb 29 15:39:40 phop5 /netbsd: st0(ahc0:4:0): ststrategy 65536 bytes @ blk 1613568
Feb 29 15:39:40 phop5 /netbsd: st0(ahc0:4:0): ststart 
Feb 29 15:39:40 phop5 /netbsd: st0(ahc0:4:0): ststart st0(ahc0:4:0): ststrategy 65536 bytes @ blk 1613696
Feb 29 15:39:40 phop5 /netbsd: st0(ahc0:4:0): ststart st0(ahc0:4:0): ststart 
Feb 29 15:39:41 phop5 /netbsd: st0(ahc0:4:0): ststrategy 65536 bytes @ blk 1613824
Feb 29 15:39:41 phop5 /netbsd: st0(ahc0:4:0): ststart 
Feb 29 15:39:41 phop5 /netbsd: st0(ahc0:4:0): ststart st0(ahc0:4:0): ststrategy 65536 bytes @ blk 1613952
Feb 29 15:39:41 phop5 /netbsd: st0(ahc0:4:0): ststart st0(ahc0:4:0): ststart 
Feb 29 15:39:41 phop5 /netbsd: st0(ahc0:4:0): ststrategy 65536 bytes @ blk 1614080
Feb 29 15:39:41 phop5 /netbsd: st0(ahc0:4:0): ststart 
Feb 29 15:39:41 phop5 /netbsd: st0(ahc0:4:0): timed out
Feb 29 15:39:41 phop5 /netbsd: st0(ahc0:4:0): closing

	This behavior is not specific to the Adaptec 2940 SCSI controller
	used in this example. The same happens with an NCR53815 controller.

>How-To-Repeat:
	Write to Exabyte using tar (no dependency on block-size found).
	The amount of data should be of the order of 20GB.
>Fix:
	I increased the time outs in all scsi_scsi_cmd calls in st.c to
	900000 which lead to "more" seldom crashes.
>Audit-Trail:
>Unformatted: