SATA on SAS and tags

[Borja Marcos]

Hello,

I guess this is a bug. I am using SATA SSDs connecting to a SAS backplane and SAS controller (LSI2008, IT firmware, mps driver)
and I've just noticed that CAM claims a maximum of 255 tags. 

Shouldn't it be 16 using NCQ instead of TCQ?


mps0: <LSI SAS2008> port 0xfc00-0xfcff mem 0xdf2b0000-0xdf2bffff,0xdf2c0000-0xdf2fffff irq 32 at device 0.0 on pci2
mps0: Firmware: 18.00.00.00, Driver: 16.00.00.00-fbsd
mps0: IOCCapabilities: 1285c<ScsiTaskFull,DiagTrace,SnapBuf,EEDP,TransRetry,EventReplay,HostDisc>

camcontrol devlist
# camcontrol devlist
<SEAGATE ST9146803SS FS64>         at scbus0 target 8 lun 0 (pass0,da0)
<SEAGATE ST9146803SS FS64>         at scbus0 target 9 lun 0 (pass1,da1)
<ATA Samsung SSD 840 BB0Q>         at scbus0 target 10 lun 0 (da2,pass2)
<ATA Samsung SSD 840 AB0Q>         at scbus0 target 11 lun 0 (da3,pass3)
<ATA Samsung SSD 840 BB0Q>         at scbus0 target 12 lun 0 (da4,pass4)
<ATA Samsung SSD 840 BB0Q>         at scbus0 target 13 lun 0 (pass5,da5)
<ATA Samsung SSD 840 BB0Q>         at scbus0 target 14 lun 0 (da6,pass6)
<ATA Samsung SSD 840 BB0Q>         at scbus0 target 15 lun 0 (da7,pass7)
<ATA Samsung SSD 840 AB0Q>         at scbus0 target 17 lun 0 (da8,pass8)
<ATA Samsung SSD 840 BB0Q>         at scbus0 target 18 lun 0 (da9,pass9)
<ATA Samsung SSD 840 AB0Q>         at scbus0 target 19 lun 0 (da10,pass10)
<ATA Samsung SSD 840 AB0Q>         at scbus0 target 20 lun 0 (da11,pass11)
<ATA Samsung SSD 840 BB0Q>         at scbus0 target 21 lun 0 (da12,pass12)
<ATA Samsung SSD 840 BB0Q>         at scbus0 target 25 lun 0 (da13,pass13)


# camcontrol tags da10 -v
(pass10:mps0:0:19:0): dev_openings  255
(pass10:mps0:0:19:0): dev_active    0
(pass10:mps0:0:19:0): devq_openings 255
(pass10:mps0:0:19:0): devq_queued   0
(pass10:mps0:0:19:0): held          -63
(pass10:mps0:0:19:0): mintags       2
(pass10:mps0:0:19:0): maxtags       255


Thanks!





Borja.