[pulseaudio-discuss] [RFC] Alsa UCM integration.

pl bossart bossart.nospam at gmail.com
Mon Feb 7 19:05:53 PST 2011

Hi Margarita,

> I've created some code that can read this data out of UCM in module
> alsa-card but I'm now looking for the best way to store this into the
> prop list for the sound card. e.g. should I extend intended roles
> proplist or add new proplist types for UCM.

As I wrote in my comments on alsa-devel, I don't think it's right to
read UCM properties in module-alsa-card. For virtual cards, eg. a USB
headphone and a USB microphone, you will have 2 cards part used for
the same verb. It'd be weird to store UCM values twice. In addition,
somehow we have to reconcile the static list of cards/devices in UCM
configurations with the way PulseAudio detects hardware.

I would think UCM information should be stored in a core proplist by a
standalone module that runs on startup (before module-udev-detect),
and when a card is detected with udev events you can identify in
module-alsa-card which configuration to use. Only then can you set the
UCM verb/devices for that specific card based on the role indicated by

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