OW19982: AHHC MPC HUNG PREQC PFDSC

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• Problem is very similar to what is described in OW13944.
  OW13944 is already applied.
  An AHHC connection is defined with 2 READ and 2 WRITE
  subchannel.  One of the WRITE/READ subchannel pairs went
  inoperative.  IST1222I and IST259I INOP 01 were issued.
  During recovery of the connection, ACTLINK processing causes a
  DCM channel command to occur.  An interrupt
  occurred for DCM channel program.  VTAM does not see this
  interrupt because CC3 posting is disabled for activation flows.
  IST574E START I/O TIMEOUT message is issued when the timeout
  value expires.  NCBBUSYF is left on and the AHHC connection is
  inoperative at the point.  Subsequent
  V NET,INACT,F,ID=localsnapu commands do not complete.
  Note : A similar problem can occur with a CTC or MPC
  connection during activation flows.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All MPC / AHHC / HPR users.                  *
  ****************************************************************
  * PROBLEM DESCRIPTION: Channels can hang in PREQC or PFDSC     *
  *                      after attemptimg recovery on a channel  *
  *                      that is part of an MPC / AHHC           *
  *                      connection.                             *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  After trying to recover a channel for an MPC connection, a DCM
  is issued in Contact Wait ( XCNSSCWT x'03' ) state.  The DCM
  completes with CC3 from the channel.  The problem is that VTAM
  does not ask for CC3 posting for DCMs.  Thus, VTAM never finds
  out that the channel program has completed.  NCBBUSYF is left on
  and the CUA hang hang in PREQC or PFDSC.
  

Problem conclusion

• ISTTSCIO has been changed to request CC3 posting in reset and
  contact wait states during activation.
  

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:

  UW28141 UW28142 UW28143

Modules/Macros

• ISTTSCIO ISTTSC8E
  

Fix information

• Fixed component name

  VTAM V4 MVS/ESA

• Fixed component ID

  569511701

Applicable component levels

• R101 PSY UW28141

     UP96/05/14 P F605

• R201 PSY UW28142

     UP96/05/14 P F605

• R301 PSY UW28143

     UP96/05/14 P F605

Fix is available

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