101 lines
3.4 KiB
Diff
101 lines
3.4 KiB
Diff
From: Thomas Gleixner <tglx@linutronix.de>
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Date: Thu, 23 Nov 2017 16:39:15 +0100
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Subject: [PATCH 34/36] ALSA/dummy: Replace tasklet with softirq hrtimer
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.14/older/patches-4.14.15-rt11.tar.xz
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The tasklet is used to defer the execution of snd_pcm_period_elapsed() to
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the softirq context. Using the HRTIMER_MODE_SOFT mode invokes the timer
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callback in softirq context as well which renders the tasklet useless.
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[o-takashi: avoid stall due to a call of hrtimer_cancel() on a callback
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of hrtimer]
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
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Cc: alsa-devel@alsa-project.org
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Cc: Takashi Sakamoto <o-takashi@sakamocchi.jp>
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Cc: Takashi Iwai <tiwai@suse.com>
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Cc: Jaroslav Kysela <perex@perex.cz>
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Link: http://lkml.kernel.org/r/20170905161820.jtysvxtfleunbbmf@breakpoint.cc
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Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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---
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sound/drivers/dummy.c | 27 ++++++++++++---------------
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1 file changed, 12 insertions(+), 15 deletions(-)
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--- a/sound/drivers/dummy.c
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+++ b/sound/drivers/dummy.c
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@@ -376,17 +376,9 @@ struct dummy_hrtimer_pcm {
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ktime_t period_time;
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atomic_t running;
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struct hrtimer timer;
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- struct tasklet_struct tasklet;
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struct snd_pcm_substream *substream;
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};
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-static void dummy_hrtimer_pcm_elapsed(unsigned long priv)
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-{
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- struct dummy_hrtimer_pcm *dpcm = (struct dummy_hrtimer_pcm *)priv;
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- if (atomic_read(&dpcm->running))
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- snd_pcm_period_elapsed(dpcm->substream);
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-}
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-
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static enum hrtimer_restart dummy_hrtimer_callback(struct hrtimer *timer)
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{
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struct dummy_hrtimer_pcm *dpcm;
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@@ -394,7 +386,14 @@ static enum hrtimer_restart dummy_hrtime
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dpcm = container_of(timer, struct dummy_hrtimer_pcm, timer);
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if (!atomic_read(&dpcm->running))
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return HRTIMER_NORESTART;
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- tasklet_schedule(&dpcm->tasklet);
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+ /*
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+ * In cases of XRUN and draining, this calls .trigger to stop PCM
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+ * substream.
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+ */
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+ snd_pcm_period_elapsed(dpcm->substream);
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+ if (!atomic_read(&dpcm->running))
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+ return HRTIMER_NORESTART;
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+
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hrtimer_forward_now(timer, dpcm->period_time);
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return HRTIMER_RESTART;
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}
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@@ -404,7 +403,7 @@ static int dummy_hrtimer_start(struct sn
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struct dummy_hrtimer_pcm *dpcm = substream->runtime->private_data;
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dpcm->base_time = hrtimer_cb_get_time(&dpcm->timer);
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- hrtimer_start(&dpcm->timer, dpcm->period_time, HRTIMER_MODE_REL);
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+ hrtimer_start(&dpcm->timer, dpcm->period_time, HRTIMER_MODE_REL_SOFT);
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atomic_set(&dpcm->running, 1);
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return 0;
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}
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@@ -414,14 +413,14 @@ static int dummy_hrtimer_stop(struct snd
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struct dummy_hrtimer_pcm *dpcm = substream->runtime->private_data;
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atomic_set(&dpcm->running, 0);
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- hrtimer_cancel(&dpcm->timer);
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+ if (!hrtimer_callback_running(&dpcm->timer))
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+ hrtimer_cancel(&dpcm->timer);
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return 0;
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}
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static inline void dummy_hrtimer_sync(struct dummy_hrtimer_pcm *dpcm)
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{
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hrtimer_cancel(&dpcm->timer);
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- tasklet_kill(&dpcm->tasklet);
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}
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static snd_pcm_uframes_t
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@@ -466,12 +465,10 @@ static int dummy_hrtimer_create(struct s
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if (!dpcm)
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return -ENOMEM;
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substream->runtime->private_data = dpcm;
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- hrtimer_init(&dpcm->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
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+ hrtimer_init(&dpcm->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_SOFT);
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dpcm->timer.function = dummy_hrtimer_callback;
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dpcm->substream = substream;
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atomic_set(&dpcm->running, 0);
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- tasklet_init(&dpcm->tasklet, dummy_hrtimer_pcm_elapsed,
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- (unsigned long)dpcm);
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return 0;
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}
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