scsi timeouts on sgimips indy + zuluscsi

[Adrian Chadd <adrian%freebsd.org@localhost>]

hi!

I'm working on the error handling in the wdc driver when it's talking with
this zuluscsi SD SCSI emulator thing. (In parallel I'm trying to figure out
if I can configure the zuluscsi to hang less.)

Anyway, I'm looking for someone who has any idea about ye olde scsi
chipsets and the right way to handle this stuff.

Here's an example of it hanging and not resetting:

...

     Status: Command failed
    Command: /sbin/mount -rt cd9660 /dev/cd0a /mnt2
     Hit enter to continue[ 177.9141033] sd0(wdsc0:0:1:0): wdsc0: timed
out; asr=0x20 [acb 0x97ec4fa8 (flags 0x1, dleft 20)],
 <state 5, nexus 0x97ec4fa8, resid 20, msg(q 0,o 0)>sd0(wdsc0:0:1:0): ABORT
in timeout: csr=0xff, asr=0x20
[ 178.1254838] sd0(wdsc0:0:1:0): sending ABORT command
[ 178.1840412] sd0(wdsc0:0:1:0): Resetting bus
[ 180.1885505] sd0(wdsc0:0:1:0): wdsc0: timed out; asr=0x00 [acb 0x97ec4fa8
(flags 0x41, dleft 20)], <state 8, nexus 0x97ec4f
a8, resid 20, msg(q 0,o 0)>sd0(wdsc0:0:1:0): ABORT in timeout: csr=0x01,
asr=0x00
[ 180.4009330] sd0(wdsc0:0:1:0): sending ABORT command
[ 180.4594968] sd0(wdsc0:0:1:0): sending DISCONNECT to target
[ 183.4353722] wd33c93_wait: TIMEO @959 with asr=x0 csr=x1
[ 186.4119961] wd33c93_wait: TIMEO @959 with asr=x0 csr=x1
[ 189.3885164] wd33c93_wait: TIMEO @959 with asr=x0 csr=x1
[ 192.3650359] wd33c93_wait: TIMEO @959 with asr=x0 csr=x1
[ 195.3415581] wd33c93_wait: TIMEO @959 with asr=x0 csr=x1
[ 198.3180772] wd33c93_wait: TIMEO @959 with asr=x0 csr=x1
[ 201.2945987] wd33c93_wait: TIMEO @959 with asr=x0 csr=x1
[ 204.2711138] wd33c93_wait: TIMEO @959 with asr=x0 csr=x1
[ 207.2476389] wd33c93_wait: TIMEO @959 with asr=x0 csr=x1
[ 210.2241586] wd33c93_wait: TIMEO @959 with asr=x0 csr=x1
[ 213.2006735] wd33c93_wait: TIMEO @959 with asr=x0 csr=x1
[ 216.1770920] wd33c93_wait: TIMEO @959 with asr=x0 csr=x1
[ 219.1536130] wd33c93_wait: TIMEO @959 with asr=x0 csr=x1
[ 222.1302349] wd33c93_wait: TIMEO @959 with asr=x0 csr=x1
[ 225.1068634] wd33c93_wait: TIMEO @959 with asr=x0 csr=x1

...

Does anyone remember how the ye olde controller works enough to go through
the driver and figure out what could be missing with the error handling /
recovery?

eg - I have one diff already to handle a NULL pointer inside the timeout
routine:

@@ -2298,7 +2304,7 @@ wd33c93_timeout(void *arg)
                /* We need to service a missed IRQ */
                wd33c93_intr(sc);
        } else {
-               (void) wd33c93_abort(sc, sc->sc_nexus, "timeout");
+               (void) wd33c93_abort(sc, acb, "timeout");
        }
        splx(s);
 }

sc->sc_nexus is NULL after a disconnect, before the timeout fires, so that
would panic. Is using acb there instead "correct" ?

Thanks!



-adrian