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

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

[tom.ty89]

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,
-- 
2.8.2

[PATCH 3/3] libata-scsi: Do not partially report ATA read look-ahead

[tom.ty89]

From: Tom Yan <tom.ty89@gmail.com>

Nothing in the kernel actually makes use of the DRA bit in SCSI
MODE SENSE. Neither is there a sysfs file (like 'cache_type' for
WCE) that allows users to change the bit nor SCSI-ATA Translation
that can toggle the ATA feature.

Hence removing the MODE SENSE SCSI-ATA Translation that is only
triggered by the change of WCE to avoid silliness like this:
https://bugzilla.kernel.org/show_bug.cgi?id=105861#c2

Signed-off-by: Tom Yan <tom.ty89@gmail.com>

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 0295c38..8c07db8 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -2316,8 +2316,6 @@ static unsigned int ata_msense_caching(u16 *id, u8 *buf, bool changeable)
 	modecpy(buf, def_cache_mpage, sizeof(def_cache_mpage), changeable);
 	if (changeable || ata_id_wcache_enabled(id))
 		buf[2] |= (1 << 2);	/* write cache enable */
-	if (!changeable && !ata_id_rahead_enabled(id))
-		buf[12] |= (1 << 5);	/* disable read ahead */
 	return sizeof(def_cache_mpage);
 }
 
-- 
2.8.2

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

[Douglas Gilbert]

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)

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

[Tom Yan]

FWIW, the version descriptors you suggested (and the "compatibility
version") is updated for ZAC drives in:
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/drivers/ata/libata-scsi.c?id=f9ca5ab832e7ac5bc2b6fe0e82ad46d536f436f9
I have no idea why the versions for other devices are held back.

Certainly it seems right to have them updated as well. But my goal was
just to fix the typo, at least.

Not sure about the SAT version descriptor. FYR I have a few SATA/UASP
adapters (from ASMedia and JMicron), they only have the SPC-4, SBC-3
and UAS descriptor, but not a SAT one.
However unlike libata, neither of them have the "ai" VPD:
[tom@localhost ~]$ sudo sg_vpd -p ai /dev/sda
ATA information VPD page:
  SAT Vendor identification: linux
  SAT Product identification: libata
  SAT Product revision level: 3.00
  Device signature indicates SATA transport
  ATA command IDENTIFY DEVICE response summary:
    model: INTEL SSDSC2BW240A4
    serial number: CVDA339603M02403GN
    firmware revision: DC32

On 4 May 2016 at 02:19, Douglas Gilbert <dgilbert@interlog.com> wrote:
> 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)
>
>