[PATCH] ALSA: pcm: Add card sync_irq field

[Takashi Iwai]

Many PCI and other drivers performs snd_pcm_period_elapsed() simply in
its interrupt handler, so the sync_stop operation is just to call
synchronize_irq().  Instead of putting this call multiple times,
introduce the common card->sync_irq field.  When this field is set,
PCM core performs synchronize_irq() for sync-stop operation.  Each
driver just needs to copy its local IRQ number to card->sync_irq, and
that's all we need.

Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
---
 include/sound/core.h    | 1 +
 sound/core/init.c       | 1 +
 sound/core/pcm_native.c | 2 ++
 3 files changed, 4 insertions(+)

diff --git a/include/sound/core.h b/include/sound/core.h
index ee238f100f73..af3dce956c17 100644
--- a/include/sound/core.h
+++ b/include/sound/core.h
@@ -117,6 +117,7 @@ struct snd_card {
 	struct device card_dev;		/* cardX object for sysfs */
 	const struct attribute_group *dev_groups[4]; /* assigned sysfs attr */
 	bool registered;		/* card_dev is registered? */
+	int sync_irq;			/* assigned irq, used for PCM sync */
 	wait_queue_head_t remove_sleep;
 
 #ifdef CONFIG_PM
diff --git a/sound/core/init.c b/sound/core/init.c
index db99b7fad6ad..faa9f03c01ca 100644
--- a/sound/core/init.c
+++ b/sound/core/init.c
@@ -215,6 +215,7 @@ int snd_card_new(struct device *parent, int idx, const char *xid,
 	init_waitqueue_head(&card->power_sleep);
 #endif
 	init_waitqueue_head(&card->remove_sleep);
+	card->sync_irq = -1;
 
 	device_initialize(&card->card_dev);
 	card->card_dev.parent = parent;
diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index 163d621ff238..1fe581167b7b 100644
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -574,6 +574,8 @@ static void snd_pcm_sync_stop(struct snd_pcm_substream *substream)
 		substream->runtime->stop_operating = false;
 		if (substream->ops->sync_stop)
 			substream->ops->sync_stop(substream);
+		else if (substream->pcm->card->sync_irq > 0)
+			synchronize_irq(substream->pcm->card->sync_irq);
 	}
 }
 
-- 
2.16.4


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