Document fins/I0806-1
FIN #: I0806-1
SYNOPSIS: Sun Blade 1000, Sun Fire 280R and Netra 20 (T4) systems with certain
OBP revisions may fail POST with "Scan Chain Broken" error
messages
DATE: Apr/04/02
KEYWORDS: Sun Blade 1000, Sun Fire 280R and Netra 20 (T4) systems with certain
OBP revisions may fail POST with "Scan Chain Broken" error
messages
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- Sun Proprietary/Confidential: Internal Use Only -
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FIELD INFORMATION NOTICE
(For Authorized Distribution by SunService)
SYNOPSIS: Sun Blade 1000, Sun Fire 280R and Netra 20 (T4) systems with
certain OBP revisions may fail POST with "Scan Chain Broken"
error messages.
Sun Alert: No
TOP FIN/FCO REPORT: No
PRODUCT_REFERENCE: OBP 4.4.0 to 4.5.8
PRODUCT CATEGORY: Software / Service
PRODUCTS AFFECTED:
Systems Affected:
-----------------
Mkt_ID Platform Model Description Serial Number
------ -------- ----- ----------- -------------
- A28 ALL Sun Blade 1000 -
- A35 ALL Sun Fire 280R -
- N28 ALL Netra 20 -
X-Options Affected:
-------------------
Mkt_ID Platform Model Description Serial Number
------ -------- ----- ----------- -------------
- - - - -
PART NUMBERS AFFECTED:
Part number Description Model
----------- ----------- -----
501-4143-16 or below ASSY EXCALIBUR 0 MEG TSTD -
501-5938-09 or below ASSY EXCAL/LITTLENECK 0 MEG TS -
501-6230-05 or below ASSY EXCAL/LITTLENECK 0 MEG TS -
REFERENCES:
BugId: 4635979 - CPU jtag traffic not completely removed from OBP.
4632798 - POST fails with "Scan Chain Broken".
PatchId: 
111292 - Patch for the OBP 4.5.10.
ECO: WO_23524
WWStopShip: P001-20036
PROBLEM DESCRIPTION:
Sun Blade 1000, Sun Fire 280R and Netra 20 (T4) systems with Open Boot
PROM versions from 4.4.0 to 4.5.8 may fail POST with "Scan Chain
Broken" error messages. The systems should power-on, bootup, and
operate normally under the UNIX environment. However, customers or
service personnel might replace good system boards when these POST
error messages occur.
These symptoms are most likely to occur with Uni-Processor
configurations. In order to identify a failing configuration, do the
following:
At the "ok" prompt, type ".version"
This will show the resident version of OBP/POST. Versions 4.4.0
through 4.5.8 are susceptible to these errors. The error messages will
look like the following when POST is run:
.
.
0>CPMS0: 1142903b
0>CPMS1: 1142903b
0>CPMS2: 1142903b
0>CPMS3: 1142903b
0>CPMS4: 1142903b
0>CPMS5: 1142903b
0>WARNING: TEST = Initializing Scan Database
0>H/W under test = Menu Utility Device
0>MSG = Error: Idcode '0Xfffdfffd' undefined in scan database.
Update DB or error in scan ring.
0>END_WARNING
0>FCAL: 1000a12f
0>Init I2C
0>Unquiesce Safari
0>Blast Fans
0>Set Trip Temp CPU 0 to 110C
0>WED JAN 30 15:03:38 GMT 2
0>Disable Cheetah 0 error checking
0>ERROR: TEST = Disable Cheetah 0 error checking
0>H/W under test = CPU0 Basic
0>MSG = Error: Irscan Error
0>END_ERROR
0>ERROR: TEST = Disable Cheetah 0 error checking
0>H/W under test = CPU0 Basic
0>MSG = Slot 0 (Cheetah 0, SRAMs) Scan Ring Broken. Cannot Shift
0>END_ERROR
0>ERROR: TEST = Disable Cheetah 0 error checking
0>H/W under test = CPU0 Basic
0>MSG = Error: Irscan Error
0>END_ERROR
0>ERROR: TEST = Disable Cheetah 0 error checking
0>H/W under test = CPU0 Basic
0>MSG = Slot 0 (Cheetah 0, SRAMs) Scan Ring Broken. Cannot Shift
0>END_ERROR
0>ERROR: TEST = Disable Cheetah 0 error checking
0>H/W under test = CPU0 Basic
0>MSG =
*** Test Failed!! ***
0>END_ERROR
0>Safari check
0>Probe and Setup Memory
0>INFO: 1024MB Bank 0
0>INFO: No memory detected in Bank 1
0>INFO: 1024MB Bank 2
0>INFO: No memory detected in Bank 3
0>
.
.
A combination of POST, SRAMs, and the JTAG CLK buffer causes this
failure. The JTAG CLK is a free running CLK that is used in the scan
chain to scan the devices of the system during POST. The JTAG CLK
buffer (U4001) is a 5V device that drives the SRAMs on the CPU module,
which are 3.3V devices. This is an over-drive problem without proper
termination. This over-drive situation causes the SRAMs to not be
clocked properly. Thus, the SRAMs do not receive or interpret the
JTAG (scan) commands properly. When the SRAMs are in an unknown
state, they pass nonsense commands to the CPU and the scan fails.
It has been found that certain versions of the JTAG CLK buffer chip are
more susceptible to this problem. This chip can be seen at location
U4001 on the system board. Boards with Fairchild (F) buffer chips are
at higher risk than those with Texas Instruments (TI) chips.
Currently, all shipped systems passed operations testing and
inspections. Since this problem was caught in operations at the system
level testing, very FEW systems were shipped with the failing
combination. However, the potential exposure of this problem increases
when customers update their OBP/POST to versions 4.4.0 through 4.5.8.
Earlier versions of POST did not use this JTAG SCAN test feature and
will not exhibit this problem.
Engineering plans to correct the over-drive situation by replacing
the current 5V buffer device with a 3.3V version with the next fab
spin of the system board. This problem can currently be fixed with
OBP version 4.5.10 which turns off the scan test. PatchId 111292,
which contains POST/OBP 4.5.10, is now available from SunSolve.
An ECO WO_23524 has been released to change the OBP v4.4.6 to v4.5.10.
And a purge number P001-20036 is to purge all the affected SRAMs on the
CPU module.
IMPLEMENTATION:
---
| | MANDATORY (Fully Proactive)
---
---
| | CONTROLLED PROACTIVE (per Sun Geo Plan)
---
---
| X | REACTIVE (As Required)
---
CORRECTIVE ACTION:
The following recommendation is provided as a guideline for authorized
Enterprise Services Field Representatives who may encounter the above
mentioned problem.
Please adhere to the following guideline as needed:
. Disable POST:
ok setenv diag-switch? false
OR
. Install PatchId 111292 to update the OBP/POST to 4.5.10
COMMENTS:
None
============================================================================
Implementation Footnote:
i) In case of MANDATORY FINs, Enterprise Services will attempt to
contact all affected customers to recommend implementation of
the FIN.
ii) For CONTROLLED PROACTIVE FINs, Enterprise Services mission critical
support teams will recommend implementation of the FIN (to their
respective accounts), at the convenience of the customer.
iii) For REACTIVE FINs, Enterprise Services will implement the FIN as the
need arises.
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