-----Original Message----- From: Takashi Iwai [mailto:tiwai@suse.de] Sent: Friday, March 20, 2015 8:27 PM To: Jie, Yang Cc: perex@perex.cz; broonie@kernel.org; alsa-devel@alsa-project.org; Girdwood, Liam R; Liam Girdwood Subject: Re: [PATCH v2 1/2] ALSA: jack: create jack kcontrols for every jack input device
At Fri, 20 Mar 2015 12:22:10 +0000, Jie, Yang wrote:
+}
+static int snd_jack_new_kctl(struct snd_card *card, struct +snd_jack *jack, int type) {
- struct snd_kcontrol *kctl;
- struct snd_jack_kctl *jack_kctl;
- int i, err, index, state = 0 /* use 0 for default state ?? */;
- INIT_LIST_HEAD(&jack->kctl_list);
- for (i = 0; i < fls(SND_JACK_BTN_0); i++) {
int testbit = 1 << i;if (type & testbit) {With this implementation, you'll get multiple boolean kctls for a headset. I thought we agreed with creating a single boolean for headset?
[Keyon] We agreed with creating multiple kctls for combo jack, e.g.
headset.
Furthermore, e.g., imagine that type = SND_JACK_HEADSET | SND_JACK_BTN_0, we will create 3 kctls for the jack, when BTN_0 is pressed, we will report to the 3rd kctl.
Hm, I don't remember that I agreed with multiple kctls...
The multiple kctls have a significant drawback (multiple event calls for a single headset) and its behavior is incompatible with the current code (both the name change and the behavior change). That is, your patch will very likely break the existing applications.
[Keyon] I am not very clear with the existing applications that using these kctl events(seems Android use input subsystem event? Which we didn't Change here. If I understand correctly, Pulseaudio uses jack switch controls, via the name, then we can use different name for headphone and mic here.)
we will generate 2 event calls(one headphone, one mic) when Headset plug in/out, applications will receive these 2 events, and they can do anything, e.g. decide to switch on/off speaker/headphone.
BTW, I haven't implemented the generating of combo jack kctls' name yet, currently, they looked like below: numid=12,iface=CARD,name='Headset Jack' numid=13,iface=CARD,name='Headset Jack',index=1 numid=14,iface=CARD,name='Headset Jack',index=2
once we have come to agreement, we can modify it in snd_jack_new_kctl(), e.g., "Headset Jack Mic" and "Headset Jack Speakers".
Takashi