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author | 2017-10-24 22:11:21 +0200 | |
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committer | 2017-10-24 22:11:21 +0200 | |
commit | 036268ddd8c62114faf9afd4da3c35ffa2b6ecba (patch) | |
tree | 72429524bb9e4be47b760915a674e6473e305026 /Alsa-Plugin/_Alsa-Hal-plugin/README.md | |
parent | 2fd0fa8c77dbaaf40ba0812e43b6637ff1d1d76e (diff) |
Initial working version as independent repo
Diffstat (limited to 'Alsa-Plugin/_Alsa-Hal-plugin/README.md')
-rw-r--r-- | Alsa-Plugin/_Alsa-Hal-plugin/README.md | 44 |
1 files changed, 0 insertions, 44 deletions
diff --git a/Alsa-Plugin/_Alsa-Hal-plugin/README.md b/Alsa-Plugin/_Alsa-Hal-plugin/README.md deleted file mode 100644 index a6fc90d..0000000 --- a/Alsa-Plugin/_Alsa-Hal-plugin/README.md +++ /dev/null @@ -1,44 +0,0 @@ -Hal-Plugin - -Object: Add virtual soft control to sound card -Status: Proof of concept and not a usable product -Author: Fulup Ar Foll -Date : June-2017 - -HAL-plugin allows: - - to expose any existing NUMID under a customized label name, this is order to abstract sound card config. - - to add non alsa NUMID supported through a callback mechanism (eg: volume rampdown, power off, ...) - -installation - - Plugin should be placed where ever alsaplugins are located (typically: /usr/share/alsa-lib) - - Callback sharelib directory should be declare in $LD_LIBRARY_PATH - -Config -``` -cat ~/.asoundrc - ctl.agl_hal { - type afbhal - devid "hw:4" - cblib "afbhal_cb_sample.so" - ctls { - # ctlLabel {numid integer name "Alsa Ctl Name"} - MasterSwitch { numid 4 name "My_First_Control" } - MasterVol { numid 5 name "My_Second_Control" } - CB_sample { ctlcb @AfbHalSampleCB name "My_Sample_Callback"} - } - pcm.agl_hal { - type copy # Copy PCM - slave "hw:4" # Slave name - } -``` - -With such a config file - - numid=4 from sndcard=hw:4 is renamed "My_First_Control" - - numid=4 from sndcard=hw:4 is renamed "My_Second_Control" - - numid=4 will call AfbHalSampleCB from afbhal_cb_sample.so - -Note: to really implement a usable HAL at minimum every ALSA call should be implemented and read/write of values should be normalised from 0 to 100% with a step of 1. - -Conclusion: This demonstrate that implementing a HAL that both abstract ALSA get/set and enable non ALSA support is possible at an acceptable cost -without having to hack ALSA source code. The beauty of the model is than it is fully transparent to any ALSA application. The limit is that the plugin is loaded -within every application context, thus interaction with an external event loop remains complete as well as conflict management in case of share resources. |