[alsa-devel] UCM extensions

[Jaroslav Kysela]

Dne 06. 11. 19 v 12:50 Kai Vehmanen napsal(a):
> Hi Jaroslav,
> 
> On Tue, 5 Nov 2019, Jaroslav Kysela wrote:
> 
>> 	I make some internal ucm code cleanups in alsa-lib and added three
>> major extensions to allow more complex configurations which we require for the
>> SOF kernel driver.
> 
> looks very good and pragmatic way to tackle some of the issues you hit
> with current UCM.
> 
> E.g. the If block would be also sufficient to tackle the recent HDMI codec
> driver change (with a single UCM file) -- i.e. use existence of the
> hdac-hdmi driver controls to select which enable-sequences to run. Hmm, I
> like this better than trying to select a whole different UCM file based on
> which drivers are used.
> 
> And same usage pattern can be applied to other mixer control name changes
> (like you already did for the HDA mic control).
> 
> That of course leads to the question do we soon need mechanisms to
> choose between more than two conditions (e.g. if mixer controls have
> changed multiple times in recent kernels, so covering for this
> in UCM would need a Switch, If-Else, or similar). But yeah, one can
> always define another UCM, so keeping-it-simple might be the right
> choice here.

I already implemented the nested If (so you may use another If in the 
True/False blocks).

Also 'String' (equal, substring) and 'RegexMatch' conditions were added.

For the substitution, I added ${CardComponents}, too. The driver might pass 
another component description strings to the user space for a better 
identification - there is snd_component_add() kernel function for this.

>> 	I added everything to keep the interface backward compatible, so the
>> current applications should not observe any different behavior. The
>> applications like pulseaudio should use the 'hw:CARD_INDEX' specifier for the
>> open call in the future and snd_use_case_parse_ctl_elem_id() helper for the
>> element control names.
> 
> This sounds good as well. Some testing with common versions of
> e.g. Pulseaudio is probably in order to sanity check how this
> works.

Yep, I will do more testing.

Do you have any progress with the pulseaudio volume UCM extension? Could you 
send me a link to the repository again? Thank you.

					Jaroslav

> 
> Br, Kai
> 


-- 
Jaroslav Kysela <perex at perex.cz>
Linux Sound Maintainer; ALSA Project; Red Hat, Inc.