[Bug 191717] [iscsi] smartctl -H gives "ATA output registers missing" for a disk using the isci driver

[Douglas Gilbert]

On 14-07-08 07:45 AM, Martin Simmons wrote:
>>>>>> On Mon, 07 Jul 2014 23:12:27 -0400, Douglas Gilbert said:
>>
>> On 14-07-07 09:45 PM, bugzilla-noreply at freebsd.org wrote:
>>> https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=191717
>>>
>>> Mark Linimon <linimon at FreeBSD.org> changed:
>>>
>>>              What    |Removed                     |Added
>>> ----------------------------------------------------------------------------
>>>              Assignee|freebsd-bugs at FreeBSD.org    |freebsd-scsi at FreeBSD.org
>>>               Summary|smartctl -H gives "ATA      |[iscsi] smartctl -H gives
>>>                      |output registers missing"   |"ATA output registers
>>>                      |for a disk using the isci   |missing" for a disk using
>>>                      |driver                      |the isci driver
>>>
>>> --- Comment #1 from Mark Linimon <linimon at FreeBSD.org> ---
>>> Over to maintainers.
>>>
>>
>> At the point of failure "whatever" produces this SCSI sense data:
>>      f0 00 01 00 50 40 00 00  00 c2 4f 00 00 1d 00 00 00 00
>>
>> FreeBSD is wrong to print out 18 bytes because that is an 8
>> byte (deferred, fixed type) buffer because byte 7 (the
>> additional length) is 0. Whatever produced that broken
>> sense data is the probably culprit.
>>
>> It is trying to say there is "ATA pass-through information
>> available" but fails to get its message across.
>
> Hi,
>
> I'm the original reporter.
>
> The sense data is smartctl's interpretation of the ccb union.
>
> In particular, the bytes are from ccb->csio.sense_data and it calculates 18
> from ccb->csio.sense_len - ccb->csio.sense_resid (32 - 14).  I don't know if
> that is correct or not.
>
> FWIW, here is the output from CentOS 6.3 on the same machine:
>
> REPORT-IOCTL: Device=/dev/sdc Command=SMART STATUS CHECK
>   Input:   FR=0xda, SC=...., LL=...., LM=0x4f, LH=0xc2, DEV=...., CMD=0xb0
>   [ata pass-through(16): 85 06 2c 00 da 00 00 00 00 00 4f 00 c2 00 b0 00 ]
>    scsi_status=0x2, host_status=0x0, driver_status=0x8
>    info=0x1  duration=17 milliseconds  resid=0
>    >>> Sense buffer, len=22:
>   00     72 00 00 00 00 00 00 0e  09 0c 00 00 00 00 00 00
>   10     00 4f 00 c2 40 50
>    status=2: [desc] sense_key=0 asc=0 ascq=0
> Values from ATA Return Descriptor are:
>   00     09 0c 00 00 00 00 00 00  00 4f 00 c2 40 50
>   [Duration: 0.016s]
>   Output: ERR=0x00, SC=0x00, LL=0x00, LM=0x4f, LH=0xc2, DEV=0x40, STS=0x50
> REPORT-IOCTL: Device=/dev/sdc Command=SMART STATUS CHECK returned 0
>
> It appears to have the same ata pass-through command but completely different
> sense data.

The SAT standard originally only defined "descriptor" sense
data format for passing back ATA errors and warning. That is
what is being done properly in the Centos 6.3 output that
you have shown above.

More recently someone at T10 objected that SAT ignored the D_SENSE
flag which allows an application client to choose whether it wants
"fixed" or "descriptor" sense data format. It looks like the FreeBSD
case is trying to produce the equivalent "fixed" sense data, but it
fails to format it properly.

So in the FreeBSD case you are looking for the SAT Layer (SATL). It
could be in the FreeBSD CAM mid-level, the driver code or firmware,
or in a remote device like a USB bridge. However if it was in something
like a USB bridge then you would expect FreeBSD and Linux to react
the same way. So it looks like a FreeBSD bug.

Doug Gilbert