Piano 2.1 left channel broken

ashthespy · November 18, 2020, 7:22pm

I had a bit of a head scratching moment – I thought I had implemented things wrong, but as far I can tell, it’s correct. This in turn hooks into ALSA’s snd_mixer_selem_set_playback_dB_all which

Set value in dB of playback volume control for all channels of a mixer simple element.

But if the driver use two separate mixers for each channel, then it should also probably provide a Master mixer that maps to both these channels as stereo.

You can then of course set them independently for that perfect balance

amixer sset Master 40%,42%

Anyone from allo on here? Thoughts?

Okay, peeking at the driver’s source indicates that things should work as expected with the new driver?

github.com

raspberrypi/linux/blob/rpi-5.4.y/sound/soc/bcm/allo-piano-dac-plus.c#L581-L613


      
          	if (digital_gain_0db_limit) {
          		ret = snd_soc_limit_volume(card, "Master Playback Volume",
          					207);
          		if (ret < 0)
          			dev_warn(card->dev, "Failed to set volume limit: %d\n",
          				ret);
          	}
          
          	if (glb_ptr->dual_mode == 1) { //in Dual Mono Mode
          
          		ret = snd_soc_component_write(rtd->codec_dais[0]->component,
          				PCM512x_DIGITAL_VOLUME_2, (~left_val));
          		if (ret < 0)
          			return ret;
          
          		ret = snd_soc_component_write(rtd->codec_dais[1]->component,
          				PCM512x_DIGITAL_VOLUME_3, (~right_val));
          		if (ret < 0)
          			return ret;

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