On Tue, 05 Sep 2017 17:53:51 +0200, Sebastian Andrzej Siewior wrote:
From: Thomas Gleixner tglx@linutronix.de
The tasklet is used to defer the execution of snd_pcm_period_elapsed() to the softirq context. Using the CLOCK_MONOTONIC_SOFT base invokes the timer callback in softirq context as well which renders the tasklet useless.
Signed-off-by: Thomas Gleixner tglx@linutronix.de Signed-off-by: Anna-Maria Gleixner anna-maria@linutronix.de Cc: Jaroslav Kysela perex@perex.cz Cc: Takashi Iwai tiwai@suse.com Cc: Takashi Sakamoto o-takashi@sakamocchi.jp Cc: alsa-devel@alsa-project.org [o-takashi: avoid stall due to a call of hrtimer_cancel() on a callback of hrtimer] Signed-off-by: Takashi Sakamoto o-takashi@sakamocchi.jp Signed-off-by: Sebastian Andrzej Siewior bigeasy@linutronix.de
On 2017-09-02 10:19:45 [+0900], Takashi Sakamoto wrote:
Yep. I request the authors to include this
Thank you for providing a fix.
v1…v2: merged Takashi Sakamoto fixup of the original patch into v2.
So this patch now is okay?
Note that you can try it by yourself easily, as it's a dummy driver that doesn't need anything special. Just run aplay for that device (e.g. aplay -Dplughw:2 for card#2) can reproduce the original problem.
@@ -394,7 +386,12 @@ static enum hrtimer_restart dummy_hrtimer_callback(struct hrtimer *timer) dpcm = container_of(timer, struct dummy_hrtimer_pcm, timer); if (!atomic_read(&dpcm->running)) return HRTIMER_NORESTART;
- tasklet_schedule(&dpcm->tasklet);
- /* In a case of XRUN, this calls .trigger to stop PCM substream. */
As mentioned, the stop happens not only with XRUN but also in a normal situation by draining.
Other than that, looks OK to me (but not tested it).
thanks,
Takashi
- snd_pcm_period_elapsed(dpcm->substream);
- if (!atomic_read(&dpcm->running))
return HRTIMER_NORESTART;- hrtimer_forward_now(timer, dpcm->period_time); return HRTIMER_RESTART;
} @@ -414,14 +411,14 @@ static int dummy_hrtimer_stop(struct snd_pcm_substream *substream) struct dummy_hrtimer_pcm *dpcm = substream->runtime->private_data;
atomic_set(&dpcm->running, 0);
- hrtimer_cancel(&dpcm->timer);
- if (!hrtimer_callback_running(&dpcm->timer))
hrtimer_cancel(&dpcm->timer);}
static inline void dummy_hrtimer_sync(struct dummy_hrtimer_pcm *dpcm) { hrtimer_cancel(&dpcm->timer);
- tasklet_kill(&dpcm->tasklet);
}
static snd_pcm_uframes_t @@ -466,12 +463,10 @@ static int dummy_hrtimer_create(struct snd_pcm_substream *substream) if (!dpcm) return -ENOMEM; substream->runtime->private_data = dpcm;
- hrtimer_init(&dpcm->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
- hrtimer_init(&dpcm->timer, CLOCK_MONOTONIC_SOFT, HRTIMER_MODE_REL); dpcm->timer.function = dummy_hrtimer_callback; dpcm->substream = substream; atomic_set(&dpcm->running, 0);
- tasklet_init(&dpcm->tasklet, dummy_hrtimer_pcm_elapsed,
(unsigned long)dpcm);}
-- 2.14.1