"scsi bus continuously busy"

[Alan Perry]

On 5/2/20 10:44 AM, Warner Losh wrote:
> 
> 
> On Sat, May 2, 2020 at 11:22 AM Alan Perry via cctalk 
> <cctalk at classiccmp.org <mailto:cctalk at classiccmp.org>> wrote:
> 
>     Courtesy of a Raspberry Pi serving as the ND server, I am now able to
>     load SunOS 3.5 over the network onto my 3/260 and it is now coming up
>     into the OS. I am now seeing this error:
> 
>       >sc0 at vme24d16 200000 vec 0x40
>       >sd0 at sc0 slave 0
>       >si0:  sc_cmd:  scsi bus continuously busy
>       >sc0:  resetting scsi bus
>       >sd1 at sc0 slave 1
>       >si0:  sc_cmd:  scsi bus continuously busy
>       >sc0:  resetting scsi bus
> 
>     The SCSI controller is the "Sun 2" SCSI card. I saw some corrosion-ish
>     crap on the board and cleaned it off. It is SCSI, so, of course, I
>     played with termination. No change in behavior.
> 
>     Is this likely to be a controller board problem or a device problem?
> 
>     Are these boards picky about SCSI devices?
> 
>     _Any other suggestions?_
> 
> 
> This comes from code:
>                  /* wait for scsi bus to become free */
>                  for (j = 0; j < SI_WAIT_COUNT/4; j++) {
>                          if ((SBC_RD.cbsr & SBC_CBSR_BSY) == 0)
>                                  goto SI_ARB_SEL_FREE;
> ...
>                  }
>                  printf("si%d:  si_arb_sel: scsi bus continuously busy\n",
>                          SINUM(c));
> 
> So the busy bit is stuck on and there's no reselect that happens. The 
> chip in question is NCR 5380 SBC. This is a phase issue on the bus. 
> After 10s the busy bit in this controller didn't clear. I didn't look it 
> up, but I'll wager that's the BSY bit on the bus not clearing. This 
> suggests an electrical issue (maybe termination, maybe not, so not 
> surprised it didn't help since this is a signal line, not a data line).
> 
> Does this happen with no devices on the bus?

sc0 at vme24d16 200000 vec 0x40
sd0 at sc0 slave 0
sd1 at sc0 slave 1
sd2 at sc0 slave 8
st0 at sc0 slave 32
st1 at sc0 slave 40
zs0 at obio 20000 pri 3
zs1 at obio 0 pri 3
ie0 at obio c0000 pri 3
bwtwo0 at obmem ff000000 pri 4
bwtwo0: resolution 1152 x 900
sd0:  scsi bus failure
sc0:  sd0, unit offline
sd0:  scsi bus failure
sc0:  sd0, unit offline
root on nd0

> 
> Warner