Re: sas_device/end_device-*/phy_identifier flipped

[Douglas Gilbert <dougg@torque.net>]

Luben Tuikov wrote:
> --- Douglas Gilbert <dougg@torque.net> wrote:
>> In lk 2.6.20-rc2 (and probably earlier) the phy_identifier
>> attribute in the /sys/class/sas_device/end_device-*
>> directory is showing the wrong end of the point to point
>> link.
>>
>> Phy identifiers on (dual ported) SAS disks are typically
>> 0 and 1. For SATA disks the phy identifier should be 0.
>>
>> # lsscsi
>> [4:0:0:0]    disk    ATA      ST3160812AS      D     /dev/sda
>> [4:0:1:0]    disk    SEAGATE  ST336754SS       0003  /dev/sdb
>> # lsscsi -t
>> [4:0:0:0]    disk    sas:0x500605b0000033e6          /dev/sda
>> [4:0:1:0]    disk    sas:0x5000c500005208ee          /dev/sdb
>> # lsscsi -tL 4:0:1:0
>> [4:0:1:0]    disk    sas:0x5000c500005208ee          /dev/sdb
>>   transport=sas
>>   initiator_port_protocols=none
>>   initiator_response_timeout=10000
>>   I_T_nexus_loss_timeout=1744
>>   phy_identifier=7
>>   ready_led_meaning=1
>>   sas_address=0x5000c500005208ee
>>   target_port_protocols=ssp
>>
>> # smp_discover -mb
>> Device <500605b0000033ef>, expander (only connected phys shown):
>>   phy   5:T:attached:[500605b00006f260:03  i(SSP+STP+SMP)]  3 Gbps
>>   phy   6:T:attached:[500605b0000033e6:00  t(SATA)]  1.5 Gbps
>>   phy   7:T:attached:[5000c500005208ee:01  t(SSP)]  3 Gbps
>>
>>
>> The SATA and SAS disks are connected via an expander which
>> lets me look at sysfs for 4:0:1:0 and the expander configuration
>> with smp_discover. The port in use on the SAS disk has the
>> address: 5000c500005208ee . The expander says that cable is
>> attached to phy 1 which agrees with what I can see. However
>> sysfs reports "phy_identifier=7" which is wrong (and happens
>> to be the attached phy_id seen from the SAS disk).
>>
>> Both aic94xx and mptsas drivers do the same thing so it
>> looks like a SAS transport problem.
> 
> Have you tested this with the SAS Stack as I distribute it?

Luben,
Yes, but it is boring because it just works ***.

With your driver for a different port on the same SAS
disk, lsscsi outputs:

# lsscsi -tL 6:0:0:0
[6:0:0:0]    disk    sas:5000c500005208ed            /dev/sdd
  transport=sas
  sub_transport=sas_class
  device_name=0000000000000000
  dev_type=end device
  iproto=
  iresp_timeout=0x2710
  linkrate=3,0 Gbps
  max_linkrate=3,0 Gbps
  max_pathways=1
  min_linkrate=3,0 Gbps
  pathways=1
  ready_led_meaning=1
  rl_wlun=0
  sas_addr=5000c500005208ed
  tproto=SSP
  transport_layer_retries=0

lsscsi is data mining this directory:
/sys/class/scsi_device/6:0:0:0/device/sas_device

which contains:
# ls
device_name    itnl_timeout  max_pathways       rl_wlun
dev_type       linkrate      min_linkrate       sas_addr
iproto         LUNS          pathways           tproto
iresp_timeout  max_linkrate  ready_led_meaning  transport_layer_retries

Interestingly there is no phy_id entry (and a single
entry wouldn't be sufficient if the target was
wide port). I can live without the phy_id there (as
it can be found other ways: SMP and the protocol
specific (SAS) log page).

So the bottom line is that the phy_id(s) doesn't need
to be there but if it is it should be correct.


*** I plan to write another mail on the aic94xx
driver mess.

Doug Gilbert