From e7e17f07af23d1404a0830bbbe6feff4b3d9e0f1 Mon Sep 17 00:00:00 2001
From: John Winans <core-talk@aps.anl.gov>
Date: Fri, 24 Mar 1995 21:24:25 +0000
Subject: [PATCH] Probable race condition in PEP TX task.  Moved the final
 transmission byte assignment into the point where the busy list is locked. 
 This is how the Xycom TX task has worked all along.  This change fixed seems
 to have fixed an apparant race condition where the receive task gets a
 response to a transmitted message BEFORE the TX task gets it on the busy
 list.

---
 src/drv/drvBitBus.c | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/src/drv/drvBitBus.c b/src/drv/drvBitBus.c
index 717f09c96..944738c20 100644
--- a/src/drv/drvBitBus.c
+++ b/src/drv/drvBitBus.c
@@ -65,6 +65,10 @@
  * This driver currently needs work on error message generation.
  *
  * $Log$
+ * Revision 1.36  1994/12/16  16:11:26  winans
+ * Added debug flag guards to ALL printing.  The default debug level is set
+ * to 1 -- this provides the same output as the old version.
+ *
  * Revision 1.35  1994/12/12  16:02:57  winans
  * Rewrote the init code so that it always returns a zero (don't kill the
  * startup.cmd file.)  It is possible that this could cause some confusion
@@ -2459,10 +2463,13 @@ STATIC int pepTxTask(int link)
 	  
 	  /* Send the message in polled mode */
 	  txTCount = pnode->txMsg.length;
+
+	  /* BUG -- would be nice if we verify the length >6 here */
+
 	  txCCount = 0;
 	  txMsg = &(pnode->txMsg.length);
 
-	  while ((txCCount < txTCount) && (pBBLink[link]->abortFlag == 0)) {
+	  while ((txCCount < txTCount -1) && (pBBLink[link]->abortFlag == 0)) {
 
 	    stuck = 1000;
 	    while (((pBBLink[link]->l.PepLink.bbRegs->stat_ctl & PEP_BB_TFNF) 
@@ -2487,12 +2494,13 @@ STATIC int pepTxTask(int link)
 	      if (bbDebug>30)
 		printf("pepTxTask(%d): outputting %2.2X\n",link,0x00);
 	      pBBLink[link]->l.PepLink.bbRegs->data = 0x00;
-	    }
-	    else if (txCCount == (txTCount -1)) { /* last byte of package */
+#if 0
+	    } else if (txCCount == (txTCount -1)) { /* last byte of package */
 	      pBBLink[link]->l.PepLink.bbRegs->stat_ctl = *txMsg;
 	      if (bbDebug>30)
 		printf("pepTxTask(%d): outputting last byte %2.2X\n",
 		       link,*txMsg);
+#endif
 	    } else {                 /* regular ol' message byte */
 	      pBBLink[link]->l.PepLink.bbRegs->data = *txMsg;
 	      if (bbDebug>30)
@@ -2536,6 +2544,11 @@ STATIC int pepTxTask(int link)
 	    {
 	      /* Lock the busy list */
 	      semTake(pBBLink[link]->busyList.sem, WAIT_FOREVER);
+
+	      pBBLink[link]->l.PepLink.bbRegs->stat_ctl = *txMsg;
+	      if (bbDebug>30)
+		printf("pepTxTask(%d): outputting last byte %2.2X\n",
+		       link,*txMsg);
 	      
 	      /* set the retire time */
 	      pnode->retire = tickGet();