Timers: In Tickless mode, need to stop the interval timer before inserted a new delay into the timer list. Otherwise, the time is incorrect on the first entry of the list

1 files changed, 14 insertions, 28 deletions

diff --git a/nuttx/sched/wdog/wd_start.c b/nuttx/sched/wdog/wd_start.c
index 8488eb898..6ba19da39 100644
--- a/nuttx/sched/wdog/wd_start.c
+++ b/nuttx/sched/wdog/wd_start.c
@@ -233,9 +233,6 @@ int wd_start(WDOG_ID wdog, int delay, wdentry_t wdentry,  int argc, ...)
   FAR wdog_t *next;
   int32_t    now;
   irqstate_t saved_state;
-#ifdef CONFIG_SCHED_TICKLESS
-  bool       reassess = false;
-#endif
   int        i;
 
   /* Verify the wdog */
@@ -288,6 +285,16 @@ int wd_start(WDOG_ID wdog, int delay, wdentry_t wdentry,  int argc, ...)
       delay--;
     }
 
+#ifdef CONFIG_SCHED_TICKLESS
+  /* Cancel the interval timer that drives the timing events.  This will cause
+   * wd_timer to be called which update the delay value for the first time
+   * at the head of the timer list (there is a possibility that it could even
+   * remove it).
+   */
+
+  (void)sched_timer_cancel();
+#endif
+
   /* Do the easy case first -- when the watchdog timer queue is empty. */
 
   if (g_wdactivelist.head == NULL)
@@ -295,14 +302,6 @@ int wd_start(WDOG_ID wdog, int delay, wdentry_t wdentry,  int argc, ...)
       /* Add the watchdog to the head == tail of the queue. */
 
       sq_addlast((FAR sq_entry_t*)wdog, &g_wdactivelist);
-
-#ifdef CONFIG_SCHED_TICKLESS
-      /* Whenever the watchdog at the head of the queue changes, then we
-       * need to reassess the interval timer setting.
-       */
-
-      reassess = true;
-#endif
     }
 
   /* There are other active watchdogs in the timer queue */
@@ -348,14 +347,6 @@ int wd_start(WDOG_ID wdog, int delay, wdentry_t wdentry,  int argc, ...)
               /* Insert the watchdog at the head of the list */
 
               sq_addfirst((FAR sq_entry_t*)wdog, &g_wdactivelist);
-
-#ifdef CONFIG_SCHED_TICKLESS
-              /* If the watchdog at the head of the queue changes, then we
-               * need to reassess the interval timer setting.
-               */
-
-              reassess = true;
-#endif
             }
           else
             {
@@ -395,17 +386,12 @@ int wd_start(WDOG_ID wdog, int delay, wdentry_t wdentry,  int argc, ...)
   wdog->active = true;
 
 #ifdef CONFIG_SCHED_TICKLESS
-  /* Reassess the interval timer that will generate the next interval event.
-   * In many cases, this will be unnecessary:  This is really only necessary
-   * when the watchdog timer at the head of the queue is change.  If the
-   * timer is inserted later in the queue then the timer at the head is
-   * unchanged.
+  /* Resume the interval timer that will generate the next interval event.
+   * If the timer at the head of the list changed, then this will pick that
+   * new delay.
    */
 
-  if (reassess)
-    {
-      sched_timer_reassess();
-    }
+  sched_timer_resume();
 #endif
 
   irqrestore(saved_state);