- Problem Statement: 

    Dstop: Safari bus to CPUx Fifo underflow

- Symptoms:

    'wfail' output reports something similar to the following:

       01  redxl> dumpf load dsmd.dstop.020823.2011.07
       02  Created Fri Aug 23 20:11:08 2002
       03  By hpost v. 1.2 Generic 112488-05 May  8 2002 17:05:18  executing as pid=28804
       04  On ssc name =  scmain.
       05  Domain =  0=A = etubc12    Platform = sfgedas2
       06  Boards in dump: master SC    CPs/CSBs[1:0]: 3
       07            EXB[17:0]: 0001F
       08          Slot0[17:0]: 0001F
       09          Slot1[17:0]: 0000F
       10  -D option, -d
       11  "DSMD DomainStop Dump"
       12  0 errors occurred while creating this dump.
       13  redxl> wfail
       14  SDI EX00/S0: All SDI is DStopped and RStopped,         requested by DARB.
       15  SDI EX01/S0: All SDI is DStopped and RStopped,         requested by DARB.
       16  SDI EX02/S0  Master_Stop_Status0[31:0] = 4004004F
       17          MStop0[3:0]: All SDI logic is DStopped + Recordstopped.
       18  SDI EX02/S0  Dstop0[31:0] = 10019000
       19          Dstop0[16]: D    DARB texp requests all Dstop (M)
       20          Dstop0[28]: D 1E Slot0 asserted Error, enabled to cause Dstop (M)
       21  EPLD SB02  Err1_Dom0: Mask= 00  Err= C0  1stErr= 40
       22          Err1[6]:  1E+ Error reported by BBC0
       23          Err1[7]:      Error reported by BBC1
       24  BBC SB02/BB0   Device_Err_Stat[31:0] = 80008010
       25          DevErr[    4]:   1E  DCDS asserted error
       26  DCDSs SB02/DG0  slice 1  CPU[1:0]_Err_Stat[25:0],[30:0] = 0028002  00000000
       27          C1ES[ 1,17]:   1E+ Safari bus to CPU1 Fifo underflow
       28  FAIL Port SB2/P1:  Dstop detected by DCDS.
       29  Primary service FRU is Slot SB2.
       30  SDI EX03/S0: All SDI is DStopped and RStopped,         requested by DARB.
       31  SDI EX04/S0: Slot 0 port is DStopped, SDI is RStopped, requested by DARB.
       32  DARB C0: enabled ports (expanders)          [17:0]: 1FFFF
       33  DARB C0: other darb req Dstop+Rstop for exps[17:0]: 00004
       34  DARB C1: enabled ports (expanders)          [17:0]: 1FFFF
       35  DARB C1: other darb req Dstop+Rstop for exps[17:0]: 00004
            

- Troubleshooting:

    The dump header tells us that this Dstop was generated by dsmd (lines 10,11) 
    while a domain was active. This is also evident by the dumpf file name - 
    dsmd.dstop files are created by dsmd as part of an ASR. Walking the
    error chain:

     - The SDI on EX2 calls for Dstop as directed by its Slot 0 board, SB2 (line 20).
     - The EPLD on SB8 indicates BBC0 asserted error the first error (line 22). Also,
       BBC1 reported an accumulated error (line 23).
     - BBC0 indicates the DCDS called for error (line 25).
     - DCDS slice 1 reports a fifo underflow for CPU 1 (line 27).
     - 'wfail' FAILs SB2/P1 from the configuration to avoid the error (line 28).
     - The FRU called out is SB2 (lines 29).

    The DCDSs are slave ASICs, and all transactions are controlled via select
    commands sourced by processors. In this case, SB2/P1 tried to unload data from
    any empty queue (underflow).

    The pathways between the processors and DCDSs are entirely contained within 
    the system board, so the board is the FRU. In the general case, this error 
    could also occur on a MaxCPU board.

- Resolution:

    Repair/replace SB2.

    In general, repair/replace the board reporting the error.

- Summary of part number and patch ID's 

    http://infoserver.central.sun.com/data/syshbk/Devices/System_Board/SYSBD_SunFire_USIIICu.html
    http://infoserver.central.sun.com/data/sshandbook/Devices/CPU_Module/UltraSPARC_MaxCPU.html

- References and bug IDs

    SunSolve Article 48122 

- Additional background information

- Meta-Data/Problem categorization:

Product/Platform: SF12K/SF15K
Category:

- Keywords

15K, 12K, SF15K, SF12K, starcat, dstop, Safari bus to CPUx Fifo underflow