linux-2.6.33/snd_pcm_hw_params()

参照元†

↑

説明†

パス: linux-2.6.33/sound/core/pcm_native.c

FIXME: これは何？
- 説明

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引数†

struct snd_pcm_substream *substream
- linux-2.6.33/snd_pcm_substream
struct snd_pcm_hw_params *params
- linux-2.6.33/snd_pcm_hw_params

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返り値†

↑

参考†

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実装†

static int snd_pcm_hw_params(struct snd_pcm_substream *substream,
			     struct snd_pcm_hw_params *params)
{
	struct snd_pcm_runtime *runtime;
	int err, usecs;
	unsigned int bits;
	snd_pcm_uframes_t frames;

- linux-2.6.33/snd_pcm_runtime

linux-2.6.33/snd_pcm_uframes_t

	if (PCM_RUNTIME_CHECK(substream))
		return -ENXIO;

- linux-2.6.33/PCM_RUNTIME_CHECK()

	runtime = substream->runtime;
	snd_pcm_stream_lock_irq(substream);

- linux-2.6.33/snd_pcm_stream_lock_irq()

	switch (runtime->status->state) {
	case SNDRV_PCM_STATE_OPEN:
	case SNDRV_PCM_STATE_SETUP:
	case SNDRV_PCM_STATE_PREPARED:
		break;
	default:
		snd_pcm_stream_unlock_irq(substream);
		return -EBADFD;
	}
	snd_pcm_stream_unlock_irq(substream);

- linux-2.6.33/SNDRV_PCM_STATE_OPEN

linux-2.6.33/SNDRV_PCM_STATE_SETUP

- linux-2.6.33/SNDRV_PCM_STATE_PREPARED

linux-2.6.33/snd_pcm_stream_unlock_irq()

#if defined(CONFIG_SND_PCM_OSS) || defined(CONFIG_SND_PCM_OSS_MODULE)

- linux-2.6.33/CONFIG_SND_PCM_OSS

linux-2.6.33/CONFIG_SND_PCM_OSS_MODULE

	if (!substream->oss.oss)
#endif
		if (atomic_read(&substream->mmap_count))
			return -EBADFD;

- linux-2.6.33/atomic_read()

	params->rmask = ~0U;
	err = snd_pcm_hw_refine(substream, params);
	if (err < 0)
		goto _error;

- linux-2.6.33/snd_pcm_hw_refine()

	err = snd_pcm_hw_params_choose(substream, params);
	if (err < 0)
		goto _error;

- linux-2.6.33/snd_pcm_hw_params_choose()

	if (substream->ops->hw_params != NULL) {
		err = substream->ops->hw_params(substream, params);
		if (err < 0)
			goto _error;
	}

- substream->ops は snd_pcm_ops 型のメンバ
- linux-2.6.33/snd_pcm_ops

	runtime->access = params_access(params);
	runtime->format = params_format(params);
	runtime->subformat = params_subformat(params);
	runtime->channels = params_channels(params);
	runtime->rate = params_rate(params);
	runtime->period_size = params_period_size(params);
	runtime->periods = params_periods(params);
	runtime->buffer_size = params_buffer_size(params);
	runtime->info = params->info;
	runtime->rate_num = params->rate_num;
	runtime->rate_den = params->rate_den;

- linux-2.6.33/params_access()

linux-2.6.33/params_format()

- linux-2.6.33/params_subformat()

linux-2.6.33/params_channels()

- linux-2.6.33/params_rate()

linux-2.6.33/params_period_size()

- linux-2.6.33/params_periods()

linux-2.6.33/params_buffer_size()

	bits = snd_pcm_format_physical_width(runtime->format);
	runtime->sample_bits = bits;
	bits *= runtime->channels;
	runtime->frame_bits = bits;
	frames = 1;

- linux-2.6.33/snd_pcm_format_physical_width()

	while (bits % 8 != 0) {
		bits *= 2;
		frames *= 2;
	}
	runtime->byte_align = bits / 8;
	runtime->min_align = frames;

	/* Default sw params */
	runtime->tstamp_mode = SNDRV_PCM_TSTAMP_NONE;
	runtime->period_step = 1;
	runtime->control->avail_min = runtime->period_size;
	runtime->start_threshold = 1;
	runtime->stop_threshold = runtime->buffer_size;
	runtime->silence_threshold = 0;
	runtime->silence_size = 0;
	runtime->boundary = runtime->buffer_size;
	while (runtime->boundary * 2 <= LONG_MAX - runtime->buffer_size)
		runtime->boundary *= 2;

- linux-2.6.33/SNDRV_PCM_TSTAMP_NONE

	snd_pcm_timer_resolution_change(substream);
	runtime->status->state = SNDRV_PCM_STATE_SETUP;

- linux-2.6.33/snd_pcm_timer_resolution_change()

linux-2.6.33/SNDRV_PCM_STATE_SETUP

	pm_qos_remove_requirement(PM_QOS_CPU_DMA_LATENCY,
				substream->latency_id);

- linux-2.6.33/pm_qos_remove_requirement()

linux-2.6.33/PM_QOS_CPU_DMA_LATENCY

	if ((usecs = period_to_usecs(runtime)) >= 0)
		pm_qos_add_requirement(PM_QOS_CPU_DMA_LATENCY,
					substream->latency_id, usecs);

- linux-2.6.33/period_to_usecs()

linux-2.6.33/pm_qos_add_requirement()

	return 0;
 _error:
	/* hardware might be unuseable from this time,
	   so we force application to retry to set
	   the correct hardware parameter settings */
	runtime->status->state = SNDRV_PCM_STATE_OPEN;
	if (substream->ops->hw_free != NULL)
		substream->ops->hw_free(substream);