Use Case Configuration files
Library directories:
platforms/ codecs/ dsps/
Those directories are not inspected for the list of available UCM configurations. They contain files included from other UCMs.
UCM master configuration path lookup is defined in the top level ucm.conf file. This file allows custom directory layout. The new ucm2 layout is based on the ALSA driver name with the kernel driver name as fallback. The virtual cards (no direct hw bound) lookups are placed to the separate conf.virt.d directory.
The lookup configuration:
https://git.alsa-project.org/?p=alsa-ucm-conf.git;a=blob;f=ucm2/ucm.conf
Example paths - new conf.d scheme:
- conf.d/USB-Audio/Dell-WD15-Dock.conf -- special configuration for the Dell docking station with USB soundcard
- conf.virt.d/TwoCardsMix.conf -- virtual UCM from two soundcards
Example paths - no conf.d scheme (may be invalidated):
- USB-Audio/Dell-WD15-Dock.conf -- special configuration for the Dell docking station with USB soundcard
- TwoCardsMix/TwoCardsMix.conf -- virtual UCM from two soundcards
Note: For the driver configurations, use always the ALSA driver name or the real kernel driver name - not the ucm card name configuration paths!
The kernel driver name is obtained using sysfs like (last part of the path is used from the symlink):
/sys/class/sound/card0/device/driver
The ALSA driver name can be obtained using procfs like:
cat /proc/asound/cards
1 [NVidia ]: HDA-Intel - HDA NVidia
HDA NVidia at 0xb5080000 irq 17
driver name: HDA-Intel
card short name: HDA NVidia
card long name: HDA NVidia at 0xb5080000 irq 17
Syntax, value names
https://git.alsa-project.org/?p=alsa-lib.git;a=blob;f=include/use-case.h