[alsa-devel] UCM list/set/get

[Liam Girdwood]

On Mon, 2011-01-31 at 11:22 +0000, Mark Brown wrote:
> On Fri, Jan 28, 2011 at 11:36:47AM -0600, pl bossart wrote:
> > I've been trying to figure out what exactly needs to be filled in UCM
> > configuration files, and so far it's been a pretty frustrating
> > experience with alsa-utils/alsaucm :-(
> 
> CCing in Liam - please always remember to CC maintainers.
> 
> > The interactive mode in alsa-utils/alsaucm is broken, I fixed a couple
> > of segfaults and bad output (patches attached), but so far the only
> > thing I can do is list the verbs...It looks like
> > alsa-lib/include/use-case.h and alsa-utils/alsaucm are not aligned,
> > whenever I query with predefined identifiers alsaucm seg faults or
> > provides an error message that doesn't help much. This happens with
> > the latest code.

> > 
> > [ume at plb alsaucm]$ ./alsaucm listcards
> >   0: AudioPC
> >     this is my AudioPCI card
> >   1: SDP4430
> >     this is my SDP4430 card
> >   2: TestHDA
> >     A test HDA card
> > [ume at plb alsaucm]$ ./alsaucm -c AudioPCI list _verbs
> >   0: HiFi
> >     Play and record HiFi quality Music.
> >   1: Voice
> >     Full duplex low-power voice call
> > 
> > So far so good. Now the fun begins
> > 
> > [ume at plb alsaucm]$ ./alsaucm -c AudioPCI list _devices
> > ./alsaucm: error failed to get list _devices: No such file or directory
> > [ume at plb alsaucm]$ ./alsaucm -c AudioPCI set _verb HiFi
> > ALSA lib main.c:1250:(set_verb_user) error: failed to initialize new
> > use case: HiFi
> > ./alsaucm: error failed to set _verb=HiFi: No such device
> > [ume at plb alsaucm]$ ./alsaucm -c AudioPCI get _verb
> > ./alsaucm: error failed to get _verb: No such file or directory
> > 

It looks like we need to improve the config file error reporting here.
Adding line numbers would be good.

> > Likewise if the .conf file contains a cset in the default values, then
> > the parser fails (I took the example from src/ucm/parser.c).
> > Commenting out the cset is the only solution. What exactly is this
> > index supposed to mean?
> > SectionDefaults [
> > cdev "hw:AudioPCI"
> > cset "name='Master Playback Switch',index=2 1,1"
> > ]

Jaroslav is probably best placed to answer about the cset syntax.

The "index" is not required :-

cset "name='Master Playback Switch' 1,1"

> > 
> > [ume at plb alsaucm]$ ./alsaucm -c AudioPCI list _verbs
> > ALSA lib main.c:302:(import_master_config) Unable to execute default sequence
> > ALSA lib main.c:637:(snd_use_case_mgr_open) error: failed to import
> > AudioPCI use case configuration -19
> > ./alsaucm: error failed to open sound card AudioPCI: No such device
> > 
> > Ideally I'd like to write an interface between PulseAudio and UCM,
> > there are existing modules I can reuse to set voice or hifi modes,
> > depending on what the client roles are. But if I can't make the
> > examples work I don't think this is going to go anywhere.
> 
> There's some existing work going on with PulseAudio/UCM integration -
> Liam, I'd CC in Marga but I don't know what her new address.

I've CC'ed Margarita. She has started some work on PA and UCM
integration and has some code that can read in the UCM verbs.

Margarita, could you provide a link to your PA git.

Thanks

Liam
-- 
Freelance Developer, SlimLogic Ltd
ASoC and Voltage Regulator Maintainer.
http://www.slimlogic.co.uk