Module: xenomai-head
Branch: master
Commit: fb095979f8244d885283852a259a19ef93db8636
URL:    
http://git.xenomai.org/?p=xenomai-head.git;a=commit;h=fb095979f8244d885283852a259a19ef93db8636

Author: Philippe Gerum <r...@xenomai.org>
Date:   Fri Aug 20 07:51:59 2010 +0200

nucleus: requeue blocked non-periodic timers properly

Single-stepping into a Xenomai application should freeze timers to
avoid overruns, until the program is continued. Unfortunately,
non-periodic timers are not requeued when the time base is unblocked,
preventing their timeout handler to be fired, thus causing the tasks
pending on them to hang indefinitely.

This patch requeues those timers properly, by interval of 250 ms,
until the timebase is unlocked.

---

 ksrc/nucleus/timer.c |   23 +++++++++++++++--------
 1 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/ksrc/nucleus/timer.c b/ksrc/nucleus/timer.c
index bb9416c..aa7fce4 100644
--- a/ksrc/nucleus/timer.c
+++ b/ksrc/nucleus/timer.c
@@ -342,10 +342,10 @@ void xntimer_tick_aperiodic(void)
 {
        xnsched_t *sched = xnpod_current_sched();
        xntimerq_t *timerq = &sched->timerqueue;
+       xnticks_t now, interval;
        xntimerh_t *holder;
        xntimer_t *timer;
        xnsticks_t delta;
-       xnticks_t now;
 
        /*
         * Optimisation: any local timer reprogramming triggered by
@@ -389,13 +389,18 @@ void xntimer_tick_aperiodic(void)
                                __setbits(timer->status, XNTIMER_FIRED);
                        } else if (likely(!testbits(timer->status, 
XNTIMER_PERIODIC))) {
                                /*
-                                * Postpone the next tick to a
-                                * reasonable date in the future,
-                                * waiting for the timebase to be
-                                * unlocked at some point.
+                                * Make the blocked timer elapse again
+                                * at a reasonably close date in the
+                                * future, waiting for the timebase to
+                                * be unlocked at some point. Timers
+                                * are blocked when single-stepping
+                                * into an application using a
+                                * debugger, so it is fine to wait for
+                                * 250 ms for the user to continue
+                                * program execution.
                                 */
-                               xntimerh_date(&timer->aplink) = 
xntimerh_date(&sched->htimer.aplink);
-                               continue;
+                               interval = xnarch_ns_to_tsc(250000000ULL);
+                               goto requeue;
                        }
                } else {
                        /*
@@ -411,8 +416,10 @@ void xntimer_tick_aperiodic(void)
                                continue;
                }
 
+               interval = timer->interval;
+       requeue:
                do {
-                       xntimerh_date(&timer->aplink) += timer->interval;
+                       xntimerh_date(&timer->aplink) += interval;
                } while (xntimerh_date(&timer->aplink) < now + nklatency);
                xntimer_enqueue_aperiodic(timer);
        }


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