OA55725: ZLIB DEFLATE() CALL RETURNS Z_STREAM_ERROR (RC=-2) WITH A Z_STREAM *MSG = SYSTEM ERROR 003.

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• zLib deflate() call returns Z_STREAM_ERROR (RC=-2) with a
  z_stream *msg = System Error 003. This is a translated message
  that is generated from a RC = x'C' RSN = x'XXXX0206' from
  FPZ4ABC, compression driver. This return code / reason code
  combination indicates that the generated compression output is
  larger than the internal zEDC buffer.
  .
  Currently the zEDC driver divides compression calls into a
  certain size chunk that is delivered to the zEDC card for
  processing. In some cases this chunk is not currently small
  enough for data that is incompressible and the returned
  compressed data is not only larger than the input, it is larger
  than the output buffer.
  .
  This APAR will adjust the size of the max compression calls to a
  smaller value that will better handle data that is
  incompressible.
  

Local fix

• Manually code zLib to use 256kb data chunks for compression
  calls.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * Users at HBB7790 and above using zEDC                        *
  * compression services.                                        *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * There is a case where zEDC processing                        *
  * using zLib deflate() call returned                           *
  * a z_Stream_Error (Rc=-2) with a                              *
  * z_stream *msg = System Error 003,                            *
  * due to the compression output being                          *
  * larger than the internal zEDC buffer.                        *
  * (ZEDC/K)                                                     *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  zEDC processing using zLib deflate() call returned z_Stream_
  Error (RC=-2) with a z_stream *msg = System Error 003, due to
  the compression output being larger than the internal zEDC
  buffer. This could occur when the compression request size
  buffers and the compression symbol size is too small.
  

Problem conclusion

• Updated the logic in zEDC initialization to use a larger symbol
  size to address the buffers from over running during a
  compression request.
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

  UA98337 UA98338

Modules/Macros

• FPZINIT
  

Fix information

• Fixed component name

  PCIE SERVICES

• Fixed component ID

  5752SCIQP

Applicable component levels

• R7A0 PSY UA98338

     UP19/01/23 P F901

• R7B0 PSY UA98337

     UP19/01/23 P F901

Fix is available

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