diff options
| -rw-r--r-- | include/sound/pcm.h | 1 | ||||
| -rw-r--r-- | sound/core/pcm.c | 3 | ||||
| -rw-r--r-- | sound/core/pcm_native.c | 23 |
3 files changed, 26 insertions, 1 deletions
diff --git a/include/sound/pcm.h b/include/sound/pcm.h index 60d40b34efc0..afaf3e88e086 100644 --- a/include/sound/pcm.h +++ b/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; diff --git a/sound/core/pcm.c b/sound/core/pcm.c index bf8f412988b8..fbbbcd20c4cc 100644 --- a/sound/core/pcm.c +++ b/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; diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c index 0224c70414f5..891d7140553c 100644 --- a/sound/core/pcm_native.c +++ b/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 @@ out: 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; } |