this SS2 has run NetBSD for me for several years, and is running 1.5H quite happily,
	but -current (1.5N) fails:


	[ ... ]
	sbus0 at mainbus0 ioaddr 0xf8000000: clock = 20 MHz
	dma0 at sbus0 slot 0 offset 0x400000: rev 1+
	esp0 at sbus0 slot 0 offset 0x800000 level 3: ESP100A, 20MHz, SCSI ID 7
	scsibus0 at esp0: 8 targets, 8 luns per target
	[ ... ]
	sd3 at scsibus0 target 3 lun 0: <SEAGATE, ST1480   SUN0424, 7516> SCSI2 0/direct fixed
	sd3: 411 MB, 1476 cyl, 9 head, 63 sec, 512 bytes/sect x 843284 sectors
	[ ... ]
	root on sd3a dumps on sd3b
	dma0: error: csr=9440031e<ERR,DRAINING=3,IEN,WRITE,ENDMA,BURST=0,FASTER,ALOADED>
	esp0: DMA error; resetting
	esp0: waiting for SCSI Bus Reset to happen
	dma0: error: csr=9440031e<ERR,DRAINING=3,IEN,WRITE,ENDMA,BURST=0,FASTER,ALOADED>
	esp0: DMA error; resetting
	esp0: waiting for SCSI Bus Reset to happen
	dma0: error: csr=9440031e<ERR,DRAINING=3,IEN,WRITE,ENDMA,BURST=0,FASTER,ALOADED>
	esp0: DMA error; resetting
	esp0: waiting for SCSI Bus Reset to happen
	sd3: disk label read error
	no file system for sd3 (dev 0x718)
	cannot mount root, error = 79
	root device (default sd3a):

1) Try turning off TAG QUEUEing.

2) ncr53c9x_select() checks for an ESP100 and turns off
SELATN3.  You have an ESP100A which may have a similar
problem.  Try adding it to the switch() statement.

3) Set ncr53c9x_debug to 0xffff and see what's really
going on.

Eduardo