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Probable race condition in PEP TX task. Moved the final transmission

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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.
This commit is contained in:
John Winans
1995-03-24 21:24:25 +00:00
parent 8a23d381c4
commit e7e17f07af
1 changed files with 16 additions and 3 deletions
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19
src/drv/drvBitBus.c
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@@ -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();