[alsa-devel] HDA headset button support

[Takashi Iwai]

On Thu, 29 Nov 2018 08:22:39 +0100,
Kailang wrote:
> 
> Hi Takashi,
> 
> I test the patch.
> It will go to Max or Min volume when I press HS button up or down.
> 
> +			state = jack->button_state;
> +			if (get_jack_plug_state(jack->pin_sense))
> +				state |= jack->type;
> +			snd_jack_report(jack->jack, state);
> 			If (jack->nid == 0x55)
> 				snd_jack_report(jack->jack, 0); ==> Add this will solve keep volume up and down.
> 
> If the pin sense active, it will update Mic and Headphone state. (Upper code)
> But it still had chance to update 0x55 during unplug and plug state.
> So, Maybe need to clear the Button state. I guess.

As we don't receive button-release events, it makes sense to send the
button clear at each time, yes.

For the one-shot button event, you can handle like below.

--- a/sound/pci/hda/hda_jack.c
+++ b/sound/pci/hda/hda_jack.c
@@ -343,6 +343,11 @@ void snd_hda_jack_report_sync(struct hda_codec *codec)
 			if (get_jack_plug_state(jack->pin_sense))
 				state |= jack->type;
 			snd_jack_report(jack->jack, state);
+			if (jack->button_state) {
+				snd_jack_report(jack->jack,
+						state & ~jack->button_state);
+				jack->button_state = 0; /* button released */
+			}
 		}
 }
 EXPORT_SYMBOL_GPL(snd_hda_jack_report_sync);


thanks,

Takashi

> 
> BR,
> Kailang
> 
> -----Original Message-----
> From: Takashi Iwai <tiwai at suse.de> 
> Sent: Wednesday, November 28, 2018 10:05 PM
> To: Kailang <kailang at realtek.com>
> Cc: (alsa-devel at alsa-project.org) <alsa-devel at alsa-project.org>
> Subject: Re: HDA headset button support
> 
> On Wed, 28 Nov 2018 13:03:58 +0100,
> Kailang wrote:
> > 
> > Hi Takashi,
> > 
> > >I'd rather like to extend snd_hda_jack_add_kctl() with the key 
> > >support (maybe adding a new function).  You can pass there the 
> > >combination of SND_JACK_BTN_X with KEY_XXX in an array.
> > 
> > Do you mean create new function like below?
> > snd_hda_jack_add_key_kctl()
> > 
> > It couldn't use snd_hda_jack_add_kctl() directly.
> > Because it had report pin state and get type from NID.
> > 
> > 	type = get_input_jack_type(codec, nid);
> >         .....
> >         .....
> >  	state = snd_hda_jack_detect(codec, nid);
> > 	snd_jack_report(jack->jack, state ? jack->type : 0);
> > 
> > So, to create a new function in hda_jack.c was better.
> 
> Well, this seems more deeper than I thought.
> 
> Below is my quick attempt to add the infrastructure.  This adds more flexibility but still easiness for other possible button implementations, hopefully.
> 
> Could you check the series below?
> 
> 
> thanks,
> 
> Takashi
> 
> 
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