From: Takashi Iwai Date: Thu, 10 Nov 2016 10:10:35 +0000 (+0100) Subject: ALSA: doc: ReSTize Jack-Controls.txt X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=df3a57105c04a7bfe0874316a9e6ec968c35a6f5;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git ALSA: doc: ReSTize Jack-Controls.txt A simple conversion from a plain text file. Put to designs subdirectory. Signed-off-by: Takashi Iwai --- diff --git a/Documentation/sound/alsa/Jack-Controls.txt b/Documentation/sound/alsa/Jack-Controls.txt deleted file mode 100644 index fe1c5e0c8555..000000000000 --- a/Documentation/sound/alsa/Jack-Controls.txt +++ /dev/null @@ -1,43 +0,0 @@ -Why we need Jack kcontrols -========================== - -ALSA uses kcontrols to export audio controls(switch, volume, Mux, ...) -to user space. This means userspace applications like pulseaudio can -switch off headphones and switch on speakers when no headphones are -pluged in. - -The old ALSA jack code only created input devices for each registered -jack. These jack input devices are not readable by userspace devices -that run as non root. - -The new jack code creates embedded jack kcontrols for each jack that -can be read by any process. - -This can be combined with UCM to allow userspace to route audio more -intelligently based on jack insertion or removal events. - -Jack Kcontrol Internals -======================= - -Each jack will have a kcontrol list, so that we can create a kcontrol -and attach it to the jack, at jack creation stage. We can also add a -kcontrol to an existing jack, at anytime when required. - -Those kcontrols will be freed automatically when the Jack is freed. - -How to use jack kcontrols -========================= - -In order to keep compatibility, snd_jack_new() has been modified by -adding two params :- - - - @initial_kctl: if true, create a kcontrol and add it to the jack - list. - - @phantom_jack: Don't create a input device for phantom jacks. - -HDA jacks can set phantom_jack to true in order to create a phantom -jack and set initial_kctl to true to create an initial kcontrol with -the correct id. - -ASoC jacks should set initial_kctl as false. The pin name will be -assigned as the jack kcontrol name. diff --git a/Documentation/sound/designs/index.rst b/Documentation/sound/designs/index.rst index 798b1a44bbbd..04dcdae3e4f2 100644 --- a/Documentation/sound/designs/index.rst +++ b/Documentation/sound/designs/index.rst @@ -8,6 +8,7 @@ Designs and Implementations channel-mapping-api compress-offload timestamping + jack-controls procfile powersave oss-emulation diff --git a/Documentation/sound/designs/jack-controls.rst b/Documentation/sound/designs/jack-controls.rst new file mode 100644 index 000000000000..ae25b1531bb0 --- /dev/null +++ b/Documentation/sound/designs/jack-controls.rst @@ -0,0 +1,48 @@ +================== +ALSA Jack Controls +================== + +Why we need Jack kcontrols +========================== + +ALSA uses kcontrols to export audio controls(switch, volume, Mux, ...) +to user space. This means userspace applications like pulseaudio can +switch off headphones and switch on speakers when no headphones are +pluged in. + +The old ALSA jack code only created input devices for each registered +jack. These jack input devices are not readable by userspace devices +that run as non root. + +The new jack code creates embedded jack kcontrols for each jack that +can be read by any process. + +This can be combined with UCM to allow userspace to route audio more +intelligently based on jack insertion or removal events. + +Jack Kcontrol Internals +======================= + +Each jack will have a kcontrol list, so that we can create a kcontrol +and attach it to the jack, at jack creation stage. We can also add a +kcontrol to an existing jack, at anytime when required. + +Those kcontrols will be freed automatically when the Jack is freed. + +How to use jack kcontrols +========================= + +In order to keep compatibility, snd_jack_new() has been modified by +adding two params: + +initial_kctl + if true, create a kcontrol and add it to the jack list. +phantom_jack + Don't create a input device for phantom jacks. + +HDA jacks can set phantom_jack to true in order to create a phantom +jack and set initial_kctl to true to create an initial kcontrol with +the correct id. + +ASoC jacks should set initial_kctl as false. The pin name will be +assigned as the jack kcontrol name.