Re: [PATCH] Retry INQUIRY on power-on

[Mike Christie <michaelc@cs.wisc.edu>]

Hannes Reinecke wrote:
> 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.
> 

Normally, a request from the scsi scan code should go through 
scsi_softirq_done which checks for scsi_decide_disposition returning 
ADD_TO_MLQUEUE. Is aic7xxx setting the host byte to DID_REQUEUE?