[alsa-devel] Question about soc-utils
Hi Mark, ALSA SoC ML
In my understanding, "frame size" means "channel x physical width". linux/sound/core/pcm_native.c :: snd_pcm_hw_params() is doing so
static int snd_pcm_hw_params(struct snd_pcm_substream *substream, struct snd_pcm_hw_params *params) { ... => bits = snd_pcm_format_physical_width(runtime->format); runtime->sample_bits = bits; => bits *= runtime->channels; runtime->frame_bits = bits; ... }
But, soc-utils::snd_soc_params_to_frame_size() is using snd_pcm_format_width() instead of snd_pcm_format_physical_width(), In "2ch x 24bit data with 32bit width" case, above "frame_bits" will be "64", but, below "frame size" will be "48", I think. Am I wrong ?
int snd_soc_params_to_frame_size(struct snd_pcm_hw_params *params) { int sample_size;
=> sample_size = snd_pcm_format_width(params_format(params)); if (sample_size < 0) return sample_size;
=> return snd_soc_calc_frame_size(sample_size, params_channels(params), 1); }
About "TDM slot", in my understanding it is TDM channel number. TDM6 = 6ch = 6 slot, TDM8 = 8ch = 8 slot. Am I wrong ?? I'm asking because soc-utils :: snd_soc_calc_bclk() / snd_soc_calc_frame_size() have both "channles" and "slot" parameter. What is this "tdm_slots" means ?
int snd_soc_calc_frame_size(int sample_size, int channels, int tdm_slots) int snd_soc_calc_bclk(int fs, int sample_size, int channels, int tdm_slots)
Best regards --- Kuninori Morimoto
On Tue, Dec 05, 2017 at 08:01:07AM +0000, Kuninori Morimoto wrote:
But, soc-utils::snd_soc_params_to_frame_size() is using snd_pcm_format_width() instead of snd_pcm_format_physical_width(), In "2ch x 24bit data with 32bit width" case, above "frame_bits" will be "64", but, below "frame size" will be "48", I think. Am I wrong ?
That's just an oversight, it should be using the sample size.
Hi Mark
But, soc-utils::snd_soc_params_to_frame_size() is using snd_pcm_format_width() instead of snd_pcm_format_physical_width(), In "2ch x 24bit data with 32bit width" case, above "frame_bits" will be "64", but, below "frame size" will be "48", I think. Am I wrong ?
That's just an oversight, it should be using the sample size.
OK will post fixup patch
Best regards --- Kuninori Morimoto
Hi Mark, again
But, soc-utils::snd_soc_params_to_frame_size() is using snd_pcm_format_width() instead of snd_pcm_format_physical_width(), In "2ch x 24bit data with 32bit width" case, above "frame_bits" will be "64", but, below "frame size" will be "48", I think. Am I wrong ?
That's just an oversight, it should be using the sample size.
The original commit was below. It seems original code was also assuming format width. Was this also oversight ? format_width -> physical_width changes meaning, I think...
-------------------------------------------------------- commit 3d8b2ce01b2de7c3c5cbf18b9b97d26cfaf11c14 Author: Mark Brown broonie@opensource.wolfsonmicro.com Date: Mon Jan 31 20:14:38 2011 +0000
ASoC: Use snd_pcm_format_width() in snd_soc_params_to_frame_size()
Signed-off-by: Mark Brown broonie@opensource.wolfsonmicro.com Acked-by: Liam Girdwood lrg@slimlogic.co.uk
diff --git a/sound/soc/soc-utils.c b/sound/soc/soc-utils.c index 1d07b93..3f45e6a 100644 --- a/sound/soc/soc-utils.c +++ b/sound/soc/soc-utils.c @@ -28,26 +28,9 @@ int snd_soc_params_to_frame_size(struct snd_pcm_hw_params *params) { int sample_size;
- switch (params_format(params)) { - case SNDRV_PCM_FORMAT_S16_LE: - case SNDRV_PCM_FORMAT_S16_BE: - sample_size = 16; - break; - case SNDRV_PCM_FORMAT_S20_3LE: - case SNDRV_PCM_FORMAT_S20_3BE: - sample_size = 20; - break; - case SNDRV_PCM_FORMAT_S24_LE: - case SNDRV_PCM_FORMAT_S24_BE: - sample_size = 24; - break; - case SNDRV_PCM_FORMAT_S32_LE: - case SNDRV_PCM_FORMAT_S32_BE: - sample_size = 32; - break; - default: - return -ENOTSUPP; - } + sample_size = snd_pcm_format_width(params_format(params)); + if (sample_size < 0) + return sample_size;
return snd_soc_calc_frame_size(sample_size, params_channels(params), 1); --------------------------------------------------------
Best regards --- Kuninori Morimoto
On Wed, Dec 06, 2017 at 05:26:54AM +0000, Kuninori Morimoto wrote:
That's just an oversight, it should be using the sample size.
The original commit was below. It seems original code was also assuming format width. Was this also oversight ? format_width -> physical_width changes meaning, I think...
- switch (params_format(params)) {
- case SNDRV_PCM_FORMAT_S16_LE:
- case SNDRV_PCM_FORMAT_S16_BE:
sample_size = 16;break;- case SNDRV_PCM_FORMAT_S20_3LE:
- case SNDRV_PCM_FORMAT_S20_3BE:
sample_size = 20;break;
Ah, sorry - I misread what you were saying. The above is the intention.
participants (2)
-
Kuninori Morimoto -
Mark Brown