[ALSA] Use posix clock monotonic for PCM and timer timestamps

[linux-2.6] / sound / core / timer.c

diff --git a/sound/core/timer.c b/sound/core/timer.c
index e7dc56ca4b97d6840f286fd1013f3cfde80731a1..7e5fe2d9166233b0874dc5a97c8f930c214e27c8 100644 (file)
--- a/sound/core/timer.c
+++ b/sound/core/timer.c
@@ -44,11 +44,14 @@
 #endif
 
 static int timer_limit = DEFAULT_TIMER_LIMIT;
+static int timer_tstamp_monotonic = 1;
 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.de>");
 MODULE_DESCRIPTION("ALSA timer interface");
 MODULE_LICENSE("GPL");
 module_param(timer_limit, int, 0444);
 MODULE_PARM_DESC(timer_limit, "Maximum global timers in system.");
+module_param(timer_tstamp_monotonic, int, 0444);
+MODULE_PARM_DESC(timer_tstamp_monotonic, "Use posix monotonic clock source for timestamps (default).");
 
 struct snd_timer_user {
        struct snd_timer_instance *timeri;
@@ -381,7 +384,10 @@ static void snd_timer_notify1(struct snd_timer_instance *ti, int event)
        struct snd_timer_instance *ts;
        struct timespec tstamp;
 
-       getnstimeofday(&tstamp);
+       if (timer_tstamp_monotonic)
+               do_posix_clock_monotonic_gettime(&tstamp);
+       else
+               getnstimeofday(&tstamp);
        snd_assert(event >= SNDRV_TIMER_EVENT_START &&
                   event <= SNDRV_TIMER_EVENT_PAUSE, return);
        if (event == SNDRV_TIMER_EVENT_START ||
@@ -1182,8 +1188,12 @@ static void snd_timer_user_tinterrupt(struct snd_timer_instance *timeri,
                spin_unlock(&tu->qlock);
                return;
        }
-       if (tu->last_resolution != resolution || ticks > 0)
-               getnstimeofday(&tstamp);
+       if (tu->last_resolution != resolution || ticks > 0) {
+               if (timer_tstamp_monotonic)
+                       do_posix_clock_monotonic_gettime(&tstamp);
+               else
+                       getnstimeofday(&tstamp);
+       }
        if ((tu->filter & (1 << SNDRV_TIMER_EVENT_RESOLUTION)) &&
            tu->last_resolution != resolution) {
                r1.event = SNDRV_TIMER_EVENT_RESOLUTION;