Re: [PATCH] ALSA: hda/conexant: Set mic pin VREF to 0x24 on headset mic plug

On Tue, 25 Aug 2026 04:38:55 +0200,
songxiebing wrote:
> 
> From: Bob Song <[email protected]>
> 
> For 3-pole headset microphones, the mic pin VREF must always be
> configured to 0x24 regardless of the headset type, otherwise the
> mic will not be able to record audio. Move the setting of the mic
> pin widget control to a common path.
> 
> Signed-off-by: Bob Song <[email protected]>
> ---
>  sound/hda/codecs/conexant.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/sound/hda/codecs/conexant.c b/sound/hda/codecs/conexant.c
> index 40da2832ba66..a18091a2866f 100644
> --- a/sound/hda/codecs/conexant.c
> +++ b/sound/hda/codecs/conexant.c
> @@ -225,13 +225,12 @@ static void cx_process_headset_plugin(struct hda_codec *codec)
>  	val = snd_hda_codec_read(codec, 0x1c, 0, 0xcb0, 0x0);
>  	if (val & 0x800) {
>  		codec_dbg(codec, "headset plugin, type is CTIA\n");
> -		snd_hda_codec_write(codec, 0x19, 0, AC_VERB_SET_PIN_WIDGET_CONTROL, 0x24);
>  	} else if (val & 0x400) {
>  		codec_dbg(codec, "headset plugin, type is OMTP\n");
> -		snd_hda_codec_write(codec, 0x19, 0, AC_VERB_SET_PIN_WIDGET_CONTROL, 0x24);
>  	} else {
> -		codec_dbg(codec, "headphone plugin\n");
> +		codec_dbg(codec, "mic plugin\n");
>  	}
> +	snd_hda_codec_write(codec, 0x19, 0, AC_VERB_SET_PIN_WIDGET_CONTROL, 0x24);
>  }


Hmm, it's a headset plug check code, and the fallback case you
modified was supposed to be a headphone jack, no microphone.  That is,
the state where a headphone is plugged without microphone into the
headset jack, and in this case, it's wrong to enable the mic pin --
you shouldn't be able to record from the mic at all in this particular
case.

So, there must be other case -- mic-only plug -- and that is where the
mic pin is set up, too.


Takashi