Hi,
Some ideas, proposal for further discussion...
On Mon, 5 Oct 2009, Stefan Schmidt wrote:
Hello.
On Mon, 2009-10-05 at 11:14, Jaroslav Kysela wrote:
On Mon, 5 Oct 2009, Stefan Schmidt wrote:
On Thu, 2009-10-01 at 17:08, Stefan Schmidt wrote:
For an updated patch with all your comments inlcuded see below.
Here is another update on this patch. Fixed a problem I introduced in the last iteration and changed the config tokens from MasterPlaybackVolume to Master Playback Volume, etc. That's based on a siggestion from Mark which we had offlist. Let me quote it here to explain the good reasoning behind it.
Question: What's the IDs (integers) returned with snd_scenario_get_master_playback_volume() etc. functions?
That is part of the code Liam wrote, but let me answer it (and maybe Liam chime in if it is wrong or needs more explanation).
It's just the numid of an alsa control which should be used as master playback, etc in this scenario. It aliases the function we can use with ascenario to the real ones in alsa which can bedifferent for different scenarios.
It's not very clear. The exported functions should be documented at least with doxygen.
Also, I would move all _get_ functions to one with this interface:
#define SND_SCENARIO_KEY_KCTL_MASTER_PLAYBACK_VOLUME 1 .....
int snd_scenario_get(scenario, int key, void *result);
It will allow us to extend this interface without adding many functions in future, something like:
#define SND_SCENARIO_KEY_PCM_PLAYBACK 11 .....
Also, using numid's is not much ideal if something changes in the driver. I would prefer to use standard ctl IDs (string, index, interface - result should be snd_ctl_elem_id_t).
Please, include also some test configuration files to review the configurationsyntax.
Attached. default.conf is the main configuration file located at /etc/alsa/scenario/default.conf
Again, I would make configuration syntax compatible with other alsa-lib configuration files. The changes in the configuration files will be small and it will allow us to rewrite the code using parsers in alsa-lib.
Something like:
default.conf:
scenario."playback speaker" { file playback_spk qos HIFI "Master Playback Volume" 8 # should be rather something like: kcontrol.'Master Playback Volume' "'Master Playback Volume':33" # or a short form might be implemented (:33 is ctl_id index, ctl_id.name # would be copied from the variable key name): kcontrol.'Master Playback Volume' ":33" ... }
scenario."playback headphones" { ... }
About "playback_hs_*" files. It seems that the purpose of files is quite similar. I don't understand the reason to have 2 different descriptions.
Also, I would like to consider moving the parser from alsactl initialization code (see alsactl_init.c in alsa-utils package) to alsa-lib and use this parser also for these files. It gives much flexibility, although udev-like syntax is not ideal, I know. But we have full documentation in alsactl_init.xml, at least.
Jaroslav
----- Jaroslav Kysela perex@perex.cz Linux Kernel Sound Maintainer ALSA Project, Red Hat, Inc.