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diff --git a/conf.d/project/alsa.d/README.md b/conf.d/project/alsa.d/README.md deleted file mode 100644 index aa2a54e..0000000 --- a/conf.d/project/alsa.d/README.md +++ /dev/null @@ -1,175 +0,0 @@ - -Alsa Configuration is not complex, but it's heavy and every except intuitive. - -In order to set your configuration move step by step. And verify at each new step that you did not introduce a regression. - -### Make sure your board is not taken by PulseAudio - -* Pavucontrol is your friend. Go in device configuration and switch to off the device you want to make available to ALSA. -* Check for your device list with 'play -l'. Note that just after card number your get an alias for your sound card. - it is simpler to use this alias, card number will change depending on plug/unplug of device when this alias name - is more stable (except for few stupid driver who use 'USB' as sound card name. -* When your know your sound alias (eg:v1340 in mu case) you can test it with 'speaker-test -D v1340 -c2 -twav'. You may also - use sound card number with 'speaker-test -D hw:0 -c2 -twav'. Nevertheless as said previously this number is not stable. -* you are now ready to write your $HOME/.asoundrc config - -Note that $HOME/.asoundrc is loaded within libasound client and not by Alsa kernel, this is the reason why you do not need -to activate any control or restart a daemon for modifications to be taken in account. - -To use ALSA with AAAA and the controller you need to write 1 section in your ALSA config - -* Sound Card Mixer: Allows multiple audio stream to be played on the same sound card. If hardware support mixer, Alsa will use it. If - not it will provide mixing by software. -* Audio Role Volume: They provide independent volume for each audio role. For reference, we use Alsa softvolume, depending on - your hardware you may have this directly avaliable from your sound card. -* Authorised Audio PCM: those channel are designed for applications we do not trust and then enforce AAAA control check - before granting the access to a given channel. - -### Sound Card Mixer - -``` -pcm.SoundCardMixer { - type dmix - ipc_key 1024 - ipc_key_add_uid false - ipc_perm 0666 # mixing for all users - - # Define target effective sound card (cannot be a plugin) - slave { pcm "hw:v1340" } #Jabra Solmate - - # DMIX can only map two channels - bindings { - 0 0 - 1 1 - } -} -``` - -Warning: if you have more than one Mixer each of them should have a unique ipc_key. You sound card alias move in the slave section. -When this is done you may try your mixer with: - -``` - speaker-test -D MyMixerPCM -c2 -twav -``` - - -### Audio Role - -``` -pcm.NavigationRole { - type softvol - - # Point Slave on HOOK for policies control - slave.pcm "SoundCardMixer" - - # name should match with HAL but do not set card=xx - control.name "Playback Navigation" - -} - -``` - -The slave you point to your SoundCardMixer, and the control.name should be EXACTLY the same as the one defined in your HAL. - - -WARNING: The control here "Playback Navigation" is a user defined kernel control. It means that this kernel is created in -kernel space, but that its action happen in user space. When create those control remains visible until you reset your -sound card (eg: unplug USB), but they are save each time you reboot. It is recommended to start AAAA binder before testing -your softvol audio role channel. If you do the opposite the control will be create by Alsa Plugin and this will not inherit -of the default value you have in your HAL. - -When in place you should test it with: -``` - speaker-test -D NavigationRole -c2 -twav -``` - -IMPORTANT: control volume are attache to your physical hardware and not to intermediary level (Softvol or Mixer). To see the -newly created channel you should use -``` - amixer -Dhw:v1340 controls | grep -i playback -``` - -## Authorised Audio PCM - -This PCM is supervised with the AAAA audio hook plugin. The pluging and will any application request on this PCM and will -1st request an autorisation from AAAA controller to grant access for the client application. To do so, two things: -* the plugin should be declared (only once) -* you should declare as many authorized PCM as you need. - -### Plugin declaration - -``` -pcm_hook_type.MyHookPlugin { - install "AlsaInstallHook" - lib "/home/fulup/Workspace/AGL-AppFW/audio-bindings-dev/build/Alsa-Plugin/Alsa-Policy-Hook/policy_hook_cb.so" -} - -``` - -Lib is the path where to find AAAA Alsa hook plugin, install is the name of the init function it should not be changed. - - -When your plugin is defined you may declare your authorised PCM. Those PCM like softvol will take a slave, typically a lower -level of the audio role, or directly a mixer if your goal is to protect directly the Mixer. The AAAA Plugin hook take as - -``` -pcm.AuthorisedToNavigationOnly { - type hooks - slave.pcm "NavigationRole" - # Defined used hook sharelib and provide arguments/config to install func - hooks.0 { - type "MyHookPlugin" - hook_args { - verbose true # print few log messages (default false); - - # Every Call should return OK in order PCM to open (default timeout 100ms) - uri "ws://localhost:1234/api?token=audio-agent-token&uuid=audio-agent-session" - request { - # Request autorisation to write on navigation - RequestNavigation { - api "control" - verb "dispatch" - query "{'target':'navigation', 'args':{'device':'Jabra SOLEMATE v1.34.0'}}" - } - } - # map event reception to self generated signal - event { - pause 30 - resume 31 - stop 3 - } - } - } -} - -``` - - * The slave is the PCM that application will be transfer to if access to control is granted. - * Request is a suite à control action that respond to AGL standard application framework API - * Event is the mapping of signal an appplication will receive in case AAAA controller push event to the audio application. - -When using AAAA controller, most action should be transfert to the controller that will take action to authorise/deny the access. -Nevertheless it is also possible to directly access a lower level (e.g. call alsa Use Case Manager). People may also have their -own audio policy engine and request it directly from here. - -To test this last part your need to have a controller ready to respond to your request. Otherwise control will systematically -be denied. When your AAAA controller is ready to serve your request you may check this with -``` - amixer -Dhw:AuthorisedToMusicOnly controls | grep -i playback - amixer -Dhw:AuthorisedToNavigationOnly controls | grep -i playback -``` - -IMPORTANT: you need at least to audio role to really test this part. While you may assert with one channel that your flow -to accept/deny application works. You need two simultaneous audio stream to really play with the control. Typically when playing -music if you send a navigation message then the audio will be lower during the rendering of the navigation message. - -The action on how you lower an audio role when an other one with a higger level of priority come in place not defined at the -plugin level, but in the AAAA controller, where the API control/dispatch?target=xxxxx will execute a set of actions corresponding -the set/unset accept/deny of requested control. - -Remark: to understand what is happening it is a good idea to have an alxamixer option on the your soundcard -``` - amixer -Dhw:v1340 -``` - -(!) Do not forget to replace 'hw:v1340' by what ever is the alias of your sound card.
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