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Move the call that sets xTimeNow inside the loop that drains the timer queue to ensure higher priority tasks that pre-empt the timer daemon cannot post messages that appear to be in the future to the daemon task.

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Richard Barry 2012-11-18 09:13:39 +00:00
parent 0d421482d8
commit 2e24f1b789
1 changed files with 11 additions and 4 deletions
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15
FreeRTOS/Source/timers.c
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@ -512,10 +512,6 @@ xTIMER *pxTimer;
portBASE_TYPE xTimerListsWereSwitched, xResult; portBASE_TYPE xTimerListsWereSwitched, xResult;
portTickType xTimeNow; portTickType xTimeNow;
/* In this case the xTimerListsWereSwitched parameter is not used, but it
must be present in the function call. */
xTimeNow = prvSampleTimeNow( &xTimerListsWereSwitched );
while( xQueueReceive( xTimerQueue, &xMessage, tmrNO_DELAY ) != pdFAIL ) while( xQueueReceive( xTimerQueue, &xMessage, tmrNO_DELAY ) != pdFAIL )
{ {
pxTimer = xMessage.pxTimer; pxTimer = xMessage.pxTimer;
@ -528,6 +524,14 @@ portTickType xTimeNow;
traceTIMER_COMMAND_RECEIVED( pxTimer, xMessage.xMessageID, xMessage.xMessageValue ); traceTIMER_COMMAND_RECEIVED( pxTimer, xMessage.xMessageID, xMessage.xMessageValue );
/* In this case the xTimerListsWereSwitched parameter is not used, but
it must be present in the function call. prvSampleTimeNow() must be
called after the message is received from xTimerQueue so there is no
possibility of a higher priority task adding a message to the message
queue with a time that is ahead of the timer daemon task (because it
pre-empted the timer daemon task after the xTimeNow value was set). */
xTimeNow = prvSampleTimeNow( &xTimerListsWereSwitched );
switch( xMessage.xMessageID ) switch( xMessage.xMessageID )
{ {
case tmrCOMMAND_START : case tmrCOMMAND_START :
@ -680,3 +684,6 @@ xTIMER *pxTimer = ( xTIMER * ) xTimer;
to include software timer functionality. If you want to include software timer to include software timer functionality. If you want to include software timer
functionality then ensure configUSE_TIMERS is set to 1 in FreeRTOSConfig.h. */ functionality then ensure configUSE_TIMERS is set to 1 in FreeRTOSConfig.h. */
#endif /* configUSE_TIMERS == 1 */ #endif /* configUSE_TIMERS == 1 */