Can anyone offer clues about what's going on here?
My Sun3/80 gets a constant stream of interrupts...
(See the "dma_setup: dmasize = 6" repeats below)

[ncr53c9x_intr] regs[intr=0c,stat=17,step=04] selid=0x81 [ncr53c9x_msgin(curmsglen:0)] <msgbyte:0x80>gotmsg(80)<cmd:0x12>regs[intr=10,stat=13,step=04] STATUS_PHASE <cmd:0x11>regs[intr=08,stat=17,step=04] <stat:(0,0)><cmd:0x12>regs[intr=20,stat=10,step=04] <DISC [intr 20, stat 10, step 4]><cmd:0x44>[ncr53c9x_done(error:0)] error=0
[ncr53c9x_sched] [ncr53c9x_scsi_cmd] [0x1e, 6]->0 [ncr53c9x_sched] [ncr53c9x_select(t0,l0,cmd:1e)] dma0: start 7@0xf81a30d6,0
dma_setup: dmasize = 7
<cmd:0x80><cmd:0xc2>[ncr53c9x_intr] regs[intr=18,stat=13,step=04] dma0: intr: addr 0xf050e2, csr a10<IEN>
dmaintr: tcl=0, tcm=0, tch=0; trans=7, resid=0
STATUS_PHASE <cmd:0x11>regs[intr=08,stat=17,step=04] <stat:(10,a)>esp0: STATUS_PHASE: msg 10
<cmd:0x12>regs[intr=10,stat=12,step=04] COMMAND_PHASE 0x1e (6) dma0: start 6@0xf81a30d8,0
dma_setup: dmasize = 6
<cmd:0x80><cmd:0x90>[ncr53c9x_intr] regs[intr=10,stat=13,step=04] dma0: intr: addr 0xf050e0, csr 1210<IEN>
dmaintr: tcl=0, tcm=0, tch=0; trans=6, resid=0
STATUS_PHASE <cmd:0x11>regs[intr=08,stat=17,step=04] <stat:(2,a)>esp0: STATUS_PHASE: msg 10
<cmd:0x12>[ncr53c9x_intr] regs[intr=10,stat=12,step=04] COMMAND_PHASE 0x1e (6) dma0: start 6@0xf81a30d8,0
dma_setup: dmasize = 6
<cmd:0x80><cmd:0x90>[ncr53c9x_intr] regs[intr=10,stat=13,step=04] dma0: intr: addr 0xf050e0, csr 1210<IEN>
dmaintr: tcl=0, tcm=0, tch=0; trans=6, resid=0
STATUS_PHASE <cmd:0x11>regs[intr=08,stat=17,step=04] <stat:(2,a)>esp0: STATUS_PHASE: msg 10
<cmd:0x12>[ncr53c9x_intr] regs[intr=10,stat=12,step=04] COMMAND_PHASE 0x1e (6) dma0: start 6@0xf81a30d8,0
dma_setup: dmasize = 6
<cmd:0x80><cmd:0x90>[ncr53c9x_intr] regs[intr=10,stat=13,step=04] dma0: intr: addr 0xf050e0, csr 1210<IEN>
dmaintr: tcl=0, tcm=0, tch=0; trans=6, resid=0