Re: [PATCH] Retry INQUIRY on power-on

[Hannes Reinecke <hare@suse.de>]

James Bottomley wrote:
> On Fri, 2006-03-31 at 15:12 +0200, Hannes Reinecke wrote:
>> So we really should loosen that statement to do retry for all ASC 0x29
>> values as a power-on might well have occured without a reset.
> 
> Actually, there's probably no reason to qualify the UNIT_ATTENTION at
> all.  Any device that replies UNIT_ATTENTION to INQUIRY is out of spec,
> so it's reasonable to assume that the ASC/ASCQ responses aren't in spec
> either.  There doesn't seem to be a disadvantage to just retrying three
> times in all unit attention cases.
> 
Well, after looking through the trace I discovered it's not actually a
broken device, but rather more a driver issue:

- SCSI ML sends inquiry
- HBA cannot send message as transport parameters are invalid
- HBA requests sense
- HBA sets the sense code and returns command with code 'ADD_TO_MLQUEUE'
  to inform ML to retry the command

Only the ML fails to honour the ADD_TO_MLQUEUE code as this is
scsi_scan(), which doesn't check for it.
So if anything then rather the code in scsi_scan should been fixed to
retry the command if so advised from the LLD.

> Did you have time to look at the reset locking issue that turned up in
> the aic7xxx backport?
> 
Already sent.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke			hare@suse.de
SuSE Linux Products GmbH		S390 & zSeries
Maxfeldstraße 5				+49 911 74053 688
90409 Nürnberg				http://www.suse.de
---
Excerpt of the trace:

 4:0:10:0: scsi scan: INQUIRY pass 1 length 36
scsi_add_timer: scmd: d6d57e00, time: 1375, (e083d29e)
 4:0:10:0: send 0xd6d57e00                   4:0:10:0:
        command: Inquiry: 12 00 00 00 24 00
buffer = 0xd8baf880, bufflen = 36, done = 0xe083ec8a, queuecommand
0xe0ceeb1c
leaving scsi_dispatch_cmnd()
scsi4:A:10:0: INITIATOR_MSG_OUT byte 0x1
WDTR negotiation rejected busfree.
scsi4: ILLEGAL_PHASE 0x80
 target4:0:10: asynchronous
(scsi4:A:10:0): Unexpected command phase from packetized target
scsi4:A:10:0: Attempt to issue message failed
(scsi4:A:10:0): SCB 1: requests Check Status
(scsi4:A:10:0): Sending Sense
Copied 18 bytes of sense data at 0:
0x70 0x0 0x6 0x0 0x0 0x0 0x0 0xa 0x0 0x0 0x0 0x0 0x29 0x1 0x1 0x0
0x0 0x0
scsi_delete_timer: scmd: d6d57e00, rtn: 1
 4:0:10:0: done 0xd6d57e00 SUCCESS  8000002  4:0:10:0:
        command: Inquiry: 12 00 00 00 24 00
: Current: sense key: Unit Attention
    Additional sense: Power on occurred
scsi scan: INQUIRY failed with code 0x8000002
-
To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html