On 2019/4/4 下午6:37, Takashi Iwai wrote:
On Thu, 21 Mar 2019 17:10:07 +0100,
Pierre-Louis Bossart wrote:
+/* this may get called several times by oss emulation */
+static int sof_pcm_hw_params(struct snd_pcm_substream *substream,
+ struct snd_pcm_hw_params *params)
+{
....
+ /* container size */
+ switch (params_width(params)) {
+ case 16:
+ pcm.params.sample_container_bytes = 2;
+ break;
+ case 24:
+ pcm.params.sample_container_bytes = 4;
+ break;
+ case 32:
+ pcm.params.sample_container_bytes = 4;
+ break;
+ default:
+ return -EINVAL;
+ }
This can be simply snd_pcm_format_physical_width() / 8.
+static int sof_pcm_open(struct snd_pcm_substream *substream)
+{
....
+ /* set any runtime constraints based on topology */
+ snd_pcm_hw_constraint_step(substream->runtime, 0,
+ SNDRV_PCM_HW_PARAM_BUFFER_SIZE,
+ le32_to_cpu(caps->period_size_min));
+ snd_pcm_hw_constraint_step(substream->runtime, 0,
+ SNDRV_PCM_HW_PARAM_PERIOD_SIZE,
+ le32_to_cpu(caps->period_size_min));
Is period_size_min in frames or in bytes? The code below refers as
byte size while this refers as frames, so they look inconsistent.
Yep, you are right, we should use SNDRV_PCM_HW_PARAM_BUFFER_BYTES and
SNDRV_PCM_HW_PARAM_PERIOD_BYTES here, thanks for pointing out.
They are configured(in tplg file) following comments in
definition(somewhat confusion comparing to ALSA notion where 'size'
means in frames?) of struct snd_soc_tplg_stream_caps:
__le32 period_size_min; /* min period size bytes */
__le32 period_size_max; /* max period size bytes */
__le32 buffer_size_min; /* min buffer size bytes */
__le32 buffer_size_max; /* max buffer size bytes */
Thanks,
~Keyon
+
+ /* set runtime config */
+ runtime->hw.info = SNDRV_PCM_INFO_MMAP |
+ SNDRV_PCM_INFO_MMAP_VALID |
+ SNDRV_PCM_INFO_INTERLEAVED |
+ SNDRV_PCM_INFO_PAUSE |
+ SNDRV_PCM_INFO_RESUME |
+ SNDRV_PCM_INFO_NO_PERIOD_WAKEUP;
Does SOF support the full resume? That is, the stream gets resumed at
the exact position that was suspended. Most devices can't, hence they
don't set *_INFO_RESUME flag and let user-space restarting.
+ runtime->hw.period_bytes_min = le32_to_cpu(caps->period_size_min);
+ runtime->hw.period_bytes_max = le32_to_cpu(caps->period_size_max);
+ runtime->hw.periods_min = le32_to_cpu(caps->periods_min);
+ runtime->hw.periods_max = le32_to_cpu(caps->periods_max);
+ runtime->hw.buffer_bytes_max = le32_to_cpu(caps->buffer_size_max);
These refer as bytes...
thanks,
Takashi
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