"ata73" == "sd 72" ?

"ata73" == "sd 72" ?

[Mark Lord]

While working on sata_mv today, I noticed something weird in the syslog.
The messages from libata show "ata73" for the port with my drives (pmp),
but the messages from SCSI (sd) show "sd 72" for those same drives.

One would really think that these two numbers should agree,
not be off by one.  I wonder why they differ (or why they are
almost the same) ?

   ata73.00: ATA-7: ST3400832AS, 3.03, max UDMA/133
   ata73.00: 781422768 sectors, multi 0: LBA48 NCQ (depth 31/32)
   ata73.00: configured for UDMA/133
   ata73.02: ATA-7: ST3400832AS, 3.03, max UDMA/133
   ata73.02: 781422768 sectors, multi 0: LBA48 NCQ (depth 31/32)
   ata73.02: configured for UDMA/133
   ata73: EH complete
   ata74: SATA link down (SStatus 0 SControl 300)
   ata75: SATA link down (SStatus 0 SControl 300)
   ata76: SATA link down (SStatus 0 SControl 300)
   scsi 72:0:0:0: Direct-Access     ATA      ST3400832AS      3.03 PQ: 0 ANSI: 5
   sd 72:0:0:0: [sdb] 781422768 512-byte hardware sectors (400088 MB)
   sd 72:0:0:0: [sdb] Write Protect is off
   sd 72:0:0:0: [sdb] Mode Sense: 00 3a 00 00
   sd 72:0:0:0: [sdb] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
   sd 72:0:0:0: [sdb] 781422768 512-byte hardware sectors (400088 MB)
   sd 72:0:0:0: [sdb] Write Protect is off
   sd 72:0:0:0: [sdb] Mode Sense: 00 3a 00 00
   sd 72:0:0:0: [sdb] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
    sdb: sdb1
   sd 72:0:0:0: [sdb] Attached SCSI disk
   sd 72:0:0:0: Attached scsi generic sg2 type 0
   scsi 72:2:0:0: Direct-Access     ATA      ST3400832AS      3.03 PQ: 0 ANSI: 5
   sd 72:2:0:0: [sdc] 781422768 512-byte hardware sectors (400088 MB)
   sd 72:2:0:0: [sdc] Write Protect is off
   sd 72:2:0:0: [sdc] Mode Sense: 00 3a 00 00
   sd 72:2:0:0: [sdc] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
   sd 72:2:0:0: [sdc] 781422768 512-byte hardware sectors (400088 MB)
   sd 72:2:0:0: [sdc] Write Protect is off
   sd 72:2:0:0: [sdc] Mode Sense: 00 3a 00 00
   sd 72:2:0:0: [sdc] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA

Re: "ata73" == "sd 72" ?

[Jeff Garzik]

Mark Lord wrote:
> While working on sata_mv today, I noticed something weird in the syslog.
> The messages from libata show "ata73" for the port with my drives (pmp),
> but the messages from SCSI (sd) show "sd 72" for those same drives.
> 
> One would really think that these two numbers should agree,
> not be off by one.  I wonder why they differ (or why they are
> almost the same) ?

Just historical reasons, one counts from zero and the other does not...

	Jeff

Re: "ata73" == "sd 72" ?

[Mikael Pettersson]

Jeff Garzik writes:
 > Mark Lord wrote:
 > > While working on sata_mv today, I noticed something weird in the syslog.
 > > The messages from libata show "ata73" for the port with my drives (pmp),
 > > but the messages from SCSI (sd) show "sd 72" for those same drives.
 > > 
 > > One would really think that these two numbers should agree,
 > > not be off by one.  I wonder why they differ (or why they are
 > > almost the same) ?
 > 
 > Just historical reasons, one counts from zero and the other does not...

Could this possibly be changed, please? I've noticed this
discrepancy myself and it really is confusing.

Maybe the mapping exists in sysfs, but navigating sysfs is
an absolute nightmare IMO so I wouldn't know how to find it.

/Mikael

Re: "ata73" == "sd 72" ?

[Tejun Heo]

Mikael Pettersson wrote:
> Jeff Garzik writes:
>  > Mark Lord wrote:
>  > > While working on sata_mv today, I noticed something weird in the syslog.
>  > > The messages from libata show "ata73" for the port with my drives (pmp),
>  > > but the messages from SCSI (sd) show "sd 72" for those same drives.
>  > > 
>  > > One would really think that these two numbers should agree,
>  > > not be off by one.  I wonder why they differ (or why they are
>  > > almost the same) ?
>  > 
>  > Just historical reasons, one counts from zero and the other does not...
> 
> Could this possibly be changed, please? I've noticed this
> discrepancy myself and it really is confusing.
> 
> Maybe the mapping exists in sysfs, but navigating sysfs is
> an absolute nightmare IMO so I wouldn't know how to find it.

I hope it could be changed too but it can also irritate a lot of people. 
  :-(

-- 
tejun