esp vs. MSG_IGN_WIDE_RESIDUE

[Michael <macallan%netbsd.org@localhost>]

Hello,

I keep getting messages like this with my new old toy, and Ultra 2:
sd(0,0,0): unrecognized MESSAGE; sending REJECT

The disk is hooked to an esp/hme SBus card, so wide SCSI. I've been
using those on sparc with all sorts of disks and never saw this. It
seems harmless but seems to be followed by a drive reset /
recalibration every time, by the sound of it.
So I tried one of the known working-with-esp drives - same behaviour.
Some more digging revealed that the message in question is
MSG_IGN_WIDE_RESIDUE, which is handles only by a few drivers, and they
only ACK it and move on. 

With this patch esp should do the same ( and prints which message is
being rejected, which is kinda helpful ):

Index: ncr53c9x.c
===================================================================
RCS file: /cvsroot/src/sys/dev/ic/ncr53c9x.c,v
retrieving revision 1.147
diff -u -w -r1.147 ncr53c9x.c
--- ncr53c9x.c  11 Jan 2017 07:16:48 -0000      1.147
+++ ncr53c9x.c  11 Jun 2017 16:29:26 -0000
@@ -1837,12 +1837,15 @@
                                goto reject;
                        }
                        break;
+               case MSG_IGN_WIDE_RESIDUE:
+                       NCR_MSGS(("ignore wide residue "));
+                       break;
 
                default:
                        NCR_MSGS(("ident "));
                        scsipi_printaddr(ecb->xs->xs_periph);
-                       printf("%s: unrecognized MESSAGE; sending REJECT\n",
-                           device_xname(sc->sc_dev));
+                       printf("%s: unrecognized MESSAGE (%x); sending REJECT\n",
+                           device_xname(sc->sc_dev), sc->sc_imess[0]);
                reject:
                        ncr53c9x_sched_msgout(SEND_REJECT);
                        break;

Since I'm not familiar with low level SCSI or esp hardware - any
comments? Is this even sane? It helps here, the resets are gone and
things work normally.

have fun
Michael