---

yaml
---
r: 37614
b: refs/heads/master
c: 9442e69
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 5c87579e65ee4f419b2369407f82326d38b5d2d8
+refs/heads/master: 9442e691e4aec85eba43ac60a3e77c77fd2e73a4

trunk/include/sound/pcm.h

@@ -347,6 +347,7 @@ struct snd_pcm_substream {
 	int number;
 	char name[32];			/* substream name */
 	int stream;			/* stream (direction) */
+	char latency_id[20];		/* latency identifier */
 	size_t buffer_bytes_max;	/* limit ring buffer size */
 	struct snd_dma_buffer dma_buffer;
 	unsigned int dma_buf_id;

trunk/sound/core/pcm.c

@@ -629,6 +629,9 @@ int snd_pcm_new_stream(struct snd_pcm *pcm, int stream, int substream_count)
 		substream->number = idx;
 		substream->stream = stream;
 		sprintf(substream->name, "subdevice #%i", idx);
+		snprintf(substream->latency_id, sizeof(substream->latency_id),
+			 "ALSA-PCM%d-%d%c%d", pcm->card->number, pcm->device,
+			 (stream ? 'c' : 'p'), idx);
 		substream->buffer_bytes_max = UINT_MAX;
 		if (prev == NULL)
 			pstr->substream = substream;

trunk/sound/core/pcm_native.c

@@ -25,6 +25,7 @@
 #include <linux/file.h>
 #include <linux/slab.h>
 #include <linux/time.h>
+#include <linux/latency.h>
 #include <linux/uio.h>
 #include <sound/core.h>
 #include <sound/control.h>
@@ -347,11 +348,26 @@ static int snd_pcm_hw_refine_user(struct snd_pcm_substream *substream,
 	return err;
 }
 
+static int period_to_usecs(struct snd_pcm_runtime *runtime)
+{
+	int usecs;
+
+	if (! runtime->rate)
+		return -1; /* invalid */
+
+	/* take 75% of period time as the deadline */
+	usecs = (750000 / runtime->rate) * runtime->period_size;
+	usecs += ((750000 % runtime->rate) * runtime->period_size) /
+		runtime->rate;
+
+	return usecs;
+}
+
 static int snd_pcm_hw_params(struct snd_pcm_substream *substream,
 			     struct snd_pcm_hw_params *params)
 {
 	struct snd_pcm_runtime *runtime;
-	int err;
+	int err, usecs;
 	unsigned int bits;
 	snd_pcm_uframes_t frames;
 
@@ -431,6 +447,10 @@ static int snd_pcm_hw_params(struct snd_pcm_substream *substream,
 
 	snd_pcm_timer_resolution_change(substream);
 	runtime->status->state = SNDRV_PCM_STATE_SETUP;
+
+	remove_acceptable_latency(substream->latency_id);
+	if ((usecs = period_to_usecs(runtime)) >= 0)
+		set_acceptable_latency(substream->latency_id, usecs);
 	return 0;
  _error:
 	/* hardware might be unuseable from this time,
@@ -490,6 +510,7 @@ static int snd_pcm_hw_free(struct snd_pcm_substream *substream)
 	if (substream->ops->hw_free)
 		result = substream->ops->hw_free(substream);
 	runtime->status->state = SNDRV_PCM_STATE_OPEN;
+	remove_acceptable_latency(substream->latency_id);
 	return result;
 }