On Sat, 20 Sep 1997, Joseph R. Rach wrote:

>     [ NetBSD-1.2.1-GENERIC running on a SPARC 1+ ]
>
>     I've been having trouble with a DAT drive. It seems after some
>     random amount of the time I get:
> 
>     esp0: RESELECT: 7 bytes in FIFO!

This is the dreaded esp reselect hardware bug.  (It may be time for a
NetBSD/sparc FAQ eh?)  You may choose among several solutions:

a) change the SCSI ID of your DAT drive to something between 0 and 3
   (inclusive)
b) Edit the GENERIC config file in src/sys/arch/sparc/conf and change the
   marked line from

   # sun4c or sun4m SCSI - an NCR53c94 or equivalent behind
   # specialized DMA glue
   dma0    at sbus0 slot ? offset ?                        # on-board SCSI
*  esp0    at sbus0 slot ? offset ? flags 0xff0f           # sun4c
   esp0    at dma0 flags 0xff0f                            # sun4m

   to

   esp0    at sbus0 slot ? offset ? flags 0xffff           # sun4c

   Compile and install the new kernel.

c) Upgrade to a recent snapshot of -current, edit the file
   src/sys/dev/ic/ncr53c9x.c:413: to read

   int ncr53c9x_dmaselect = 1;

   Compile and install a new kernel.

There hasn't yet been a confirmed report that c) actually helps, but if
you feel like a pioneer, please test it and report back.

-J