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Date:   Mon, 22 May 2023 10:35:49 +0900
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Subject: Re: [PATCH v2] ata: libata-scsi: Fix get identity data failed
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To:     yangxingui <yangxingui@huawei.com>, jejb@linux.ibm.com,
        martin.petersen@oracle.com, john.g.garry@oracle.com
Cc:     linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org,
        linuxarm@huawei.com, prime.zeng@hisilicon.com,
        kangfenglong@huawei.com
References: <20230505025712.19438-1-yangxingui@huawei.com>
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 <938d6b5b-0271-977d-f046-5fd70d29b3ca@huawei.com>
From:   Damien Le Moal <dlemoal@kernel.org>
Organization: Western Digital Research
In-Reply-To: <938d6b5b-0271-977d-f046-5fd70d29b3ca@huawei.com>
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On 5/8/23 10:11, yangxingui wrote:
> 
> 
> On 2023/5/7 22:51, Damien Le Moal wrote:
>> On 2023/05/05 18:06, yangxingui wrote:
>>>
>>>
>>> On 2023/5/5 16:17, Damien Le Moal wrote:
>>>> On 2023/05/05 11:57, Xingui Yang wrote:
>>>>> The function ata_get_identity() uses the helper ata_scsi_find_dev() to get
>>>>> the ata_device structure of a scsi device. However, when the ata device is
>>>>> managed by libsas, ata_scsi_find_dev() returns NULL, turning
>>>>> ata_get_identity() into a nop and always returns -ENOMSG.
>>>>
>>>> What do you do to hit the issue ? A while back for me it was the queue depth
>>>> setting causing problems. As Garry mentioned, this led to patch 141f3d6256e5
>>>> ("ata: libata-sata: Fix device queue depth control").
>>> Attempt to return the correct value at ata_scsi_find_dev() instead of
>>> NULL, when the ata device is managed by libsas?
>>
>> That I understand. My question is *what* user operation/command triggers this ?
>> Because on my test setup, under normal use, I do not see this issue (beside what
>> was already corrected with the queue depth control). Is the issue showing up
>> when using passthrough commands only ?
> Yeah, we found that command "hdparm -i /dev/sdc" always return faild for 
> SATA HDD disk. as follows:
> [root@localhost ~]# hdparm -i /dev/sdc
> 
> /dev/sdc:
>   HDIO_GET_IDENTITY failed: Invalid argument

I cannot recreate this issue exactly like this. Here is my setup with a pm80xx
driver (Adaptec HBA):

[7:0:0:0]    disk    ATA      WDC  WUH721818AL W232  /dev/sdd   /dev/sg5
[7:0:1:0]    disk    ATA      WDC  WUH721818AL WTW2  /dev/sdi   /dev/sg6
[7:0:2:0]    disk    ATA      WDC  WUH722222AL Wf86  /dev/sdf   /dev/sg7
[7:0:3:0]    zbc     ATA      WDC  WSH722020AL W803  /dev/sdg   /dev/sg8

Using the first drive, I get:

sudo hdparm -i /dev/sdd

/dev/sdd:

 Model=WDC  WUH721818ALN604, FwRev=PCGNW232, SerialNo=3KG10LBK
 Config={ HardSect NotMFM HdSw>15uSec Fixed DTR>10Mbs }
 RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=56
 BuffType=DualPortCache, BuffSize=unknown, MaxMultSect=2, MultSect=off
 CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=4394582016
 IORDY=on/off, tPIO={min:120,w/IORDY:120}, tDMA={min:120,rec:120}
 PIO modes:  pio0 pio1 pio2 pio3 pio4
 DMA modes:  mdma0 mdma1 mdma2
 UDMA modes: udma0 udma1 udma2 udma3 udma4 udma5 *udma6
 AdvancedPM=yes: disabled (255) WriteCache=enabled
 Drive conforms to: unknown:  ATA/ATAPI-2,3,4,5,6,7

 * signifies the current active mode

So all good. However, for the following drives, I get:

sudo hdparm -i /dev/sdi

/dev/sdi:
 HDIO_GET_IDENTITY failed: No message of desired type

(same for sdf and sdg).

Will dig into this.

-- 
Damien Le Moal
Western Digital Research