Re: [PATCH 2/3] libata-scsi: Fix SCSI INQUIRY version descriptor

[Douglas Gilbert <dgilbert@interlog.com>]

On 2016-05-02 04:13 PM, tom.ty89@gmail.com wrote:
> From: Tom Yan <tom.ty89@gmail.com>
>
> https://bugzilla.kernel.org/show_bug.cgi?id=106931
> Signed-off-by: Tom Yan <tom.ty89@gmail.com>
>
> diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
> index cd30f11..0295c38 100644
> --- a/drivers/ata/libata-scsi.c
> +++ b/drivers/ata/libata-scsi.c
> @@ -1985,8 +1985,8 @@ static unsigned int ata_scsiop_inq_std(struct ata_scsi_args *args, u8 *rbuf)
>   		0x03,
>   		0x20,	/* SBC-2 (no version claimed) */
>
> -		0x02,
> -		0x60	/* SPC-3 (no version claimed) */
> +		0x03,
> +		0x00	/* SPC-3 (no version claimed) */
>   	};
>   	const u8 versions_zbc[] = {
>   		0x00,
>

SPC-3 was standardized in 2005 (ANSI INCITS 408-2005) and there
is a more recent standard: SPC-4 (ANSI INCITS 513-2015). And
my guess is that libata-scsi supports many things introduced
in SPC-4 . If you switch to SPC-4 then the "version" field in
the standard INQUIRY response (byte 2) should be changed to 6.

Also SBC-2 is old (ANSI INCITS 405-2005) and should be updated
to SBC-3 (ANSI INCITS 514-2014). Again many features supported
by libata-scsi didn't exist in SBC-2.

And libata-scsi is a SCSI to ATA Translation (SAT) layer and
there are standards for that, take your pick: SAT (ANSI INCITS
431-2007), SAT-2 (ANSI INCITS 465-2010) or SAT-3 (ANSI INCITS
517-2015).


Suggestion:
   Version descriptors             value
----------------------------------------
     SAM-5 (no version claimed)    0x00a0
     SPC-4 (no version claimed)    0x0460
     SBC-3 (no version claimed)    0x04c0
     SAT-3 (no version claimed)    0x1ee0

Plus byte 2 of INQUIRY response: 0x6

Doug Gilbert


BTW in lk 4.6.0-rc5 I see this for a directly connected SATA SSD:

# sg_inq -d /dev/sg0
standard INQUIRY:
   PQual=0  Device_type=0  RMB=0  LU_CONG=0  version=0x05  [SPC-3]
   [AERC=0]  [TrmTsk=0]  NormACA=0  HiSUP=0  Resp_data_format=2
   SCCS=0  ACC=0  TPGS=0  3PC=0  Protect=0  [BQue=0]
   EncServ=0  MultiP=0  [MChngr=0]  [ACKREQQ=0]  Addr16=0
   [RelAdr=0]  WBus16=0  Sync=0  [Linked=0]  [TranDis=0]  CmdQue=0
   [SPI: Clocking=0x0  QAS=0  IUS=0]
     length=96 (0x60)   Peripheral device type: disk
  Vendor identification: ATA
  Product identification: INTEL SSDSC2BW18
  Product revision level: DC32
  Unit serial number:

   Version descriptors:
     SAM-3 (no version claimed)
     SBC-2 (no version claimed)
     SPC-2 (no version claimed)