OK, I did this, and the resulting kernel has now been running for 4 days
without hanging, so I guess tagged queuing was the culprit in some way.

  I'm still seeing a few scsi parity errors during the execution of the
/etc/daily script, though.  (But there were none when I ran the script by
hand just after first booting the kernel.)

On Wed, Jun 20, 2001 at 11:47:22AM +0100, David Brownlee wrote:
> 	Could you try commenting out
> 		xm.xm_mode |= PERIPH_CAP_TQING
> 	in (I think)
> 		/sys/dev/ic/ncr53c9x.c
> 
> -- 
> 		David/absolute		-- www.netbsd.org: No hype required --
> 
> 
> On Tue, 19 Jun 2001, Jim Bernard wrote:
> 
> >   Same here, also on a sparc 20.  With recent kernels I occasionally see
> > scsi parity errors on one disk (can't seem to find a real hardware fault,
> > though), and eventually the system just hangs.  Some things continue to
> > work for a while after others stop working (logins via ssh seem to be one
> > of the first to go, while sendmail continues to work much longer).  I also
> > found that if I happened to be logged in while it was in this state,
> > it would eventually just not execute commands, and after a bit more time
> > even window focus changes would stop working.  The last working kernel
> > I have is 1.5U from mid April.  The first one on which I observed the
> > failure was 1.5V from May 29.  Unfortunately, that's all the info I
> > have on the problem so far.
> >
> >   BTW: I noticed that the most recent working kernel shows tagged queuing
> > rejected on all the disks, e.g.:
> >
> > sd0 at scsibus0 target 0 lun 0: <SEAGATE, ST34555N, 0930> SCSI2 0/direct fixed
> > sd0(esp0:0:0): max sync rate 10.00MB/s
> > esp0: tagged queuing rejected: target 0
> >
> > whereas the problematic kernel I built June 16 shows it enabled:
> >
> > sd0 at scsibus0 target 0 lun 0: <SEAGATE, ST34555N, 0930> SCSI2 0/direct fixed
> > sd0: 4340 MB, 6300 cyl, 8 head, 176 sec, 512 bytes/sect x 8888924 sectors
> > sd0: sync (100.0ns offset 15), 8-bit (10.000MB/s) transfers, tagged queueing
> >
> > I don't know whether this is related to the problem.
> >
> > --Jim
> >