The bias-bias-voltage should powered up/down automatically. Added missing DAPM_PRE and DAPM_POST widgets to fire up the mic_bias_event function.

--- sound/soc/codecs/sgtl5000.c +++ sound/soc/codecs/sgtl5000.c @@ -260,6 +260,9 @@ static const struct snd_soc_dapm_widget SND_SOC_DAPM_PRE("VAG_POWER_PRE", power_vag_event), SND_SOC_DAPM_POST("VAG_POWER_POST", power_vag_event), + + SND_SOC_DAPM_PRE("MIC_BIAS_PRE", mic_bias_event), + SND_SOC_DAPM_POST("MIC_BIAS_POST", mic_bias_event), }; /* routes for sgtl5000 */