[alsa-devel] UCM extensions

[Jaroslav Kysela]

Hi all,

	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.

	The first thing is the added substitution for the value strings:

https://github.com/alsa-project/alsa-lib/commit/f1e637b285e8e04e6761248a070f58f3a8fde6fc

	The second thing is the If block:

https://github.com/alsa-project/alsa-lib/commit/985715ce8148dc7ef62c8e3d8ce5a0c2ac51f8df

	The third thing is the card / hardware like specifier passed as the ucm name 
to snd_use_case_mgr_open() to support multiple card instances:

https://github.com/alsa-project/alsa-lib/commit/60164fc5886cdc6ca55eeed0c2e3f751a7d2b2c0

	All those patches (with other cleanups) are in the ucm2 branch on github for 
comments:

https://github.com/alsa-project/alsa-lib/commits/ucm2

	The proposed SOF UCM config diff is here:

https://github.com/alsa-project/alsa-ucm-conf/commit/723b6da881721488229154e923ed36413955a051
https://github.com/alsa-project/alsa-ucm-conf/commits/ucm2

	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.

	If you have another ideas to address those issues, please, let me know.

	BTW, Mark: The SOF UCM configs relies on the driver name changes, so it might 
be worth to send "ASoC: intel - fix the card names" patch to 5.4 to make 
things stable more quickly:

	https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git/commit/?h=for-5.5&id=d745cc1ab65945b2d17ec9c5652f38299c054649

				Thanks,
					Jaroslav

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