Thanks for the review! If I'm not mistaken, the microphone is attached to external codec(rt5514) instead of PCH on Kabylake platform. So there should be a TDM between DMICs and PCH. We can see in the kabylake_ssp0_hw_params function, there are some operations about setting tdm slot_width to 16 bits. Therefore, I think it only supports S16_LE format for DMICs. Is it correct? Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx> 於 2019年9月12日 週四 下午9:02寫道： > On 9/11/19 9:27 PM, Yu-Hsuan Hsu wrote: > > 24 bits recording from DMIC is not supported for KBL platform because > > the TDM slot between PCH and codec is 16 bits only. We should add a > > constraint to remove that unsupported format. > > Humm, when you use DMICs they are directly connected to the PCH with a > standard 1-bit PDM. There is no notion of TDM or slot. > > It could very well be that the firmware/topology only support 16 bit (I > vaguely recall another case where 24 bits was added), but the > description in the commit message would need to be modified to make the > reason for this change clearer. > > > > > Signed-off-by: Yu-Hsuan Hsu <yuhsuan@xxxxxxxxxxxx> > > --- > > sound/soc/intel/boards/kbl_rt5663_rt5514_max98927.c | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/sound/soc/intel/boards/kbl_rt5663_rt5514_max98927.c > b/sound/soc/intel/boards/kbl_rt5663_rt5514_max98927.c > > index 74dda8784f1a01..67b276a65a8d2d 100644 > > --- a/sound/soc/intel/boards/kbl_rt5663_rt5514_max98927.c > > +++ b/sound/soc/intel/boards/kbl_rt5663_rt5514_max98927.c > > @@ -400,6 +400,9 @@ static int kabylake_dmic_startup(struct > snd_pcm_substream *substream) > > snd_pcm_hw_constraint_list(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS, > > dmic_constraints); > > > > + runtime->hw.formats = SNDRV_PCM_FMTBIT_S16_LE; > > + snd_pcm_hw_constraint_msbits(runtime, 0, 16, 16); > > + > > return snd_pcm_hw_constraint_list(substream->runtime, 0, > > SNDRV_PCM_HW_PARAM_RATE, &constraints_rates); > > } > > > > _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx https://mailman.alsa-project.org/mailman/listinfo/alsa-devel
