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

pl bossart bossart.nospam at gmail.com
Thu Feb 24 12:20:52 PST 2011

> The initial version of the UCM module is available at the following link:
> http://git.slimlogic.co.uk/cgi-bin/cgit.cgi/pulseaudio.git/log/?h=9.20-ucm_module
> I'm still working in the module, It is work in progress to verify the
> current verb when the stream is closed, also it is needed to add more
> code to work with the profiles and the use cases. Sink, source and
> device data could be taken from the proplist of the verb, and this is
> pending too.

Hi Margarita,
I looked at your patches and have the following comments:
- any reason why your version of PulseAudio is 1.3 years old. The
previous patches on your branch are from 2009-11-18, quite a while
ago. It'll make upstreaming difficult.
- you now have a separate module-alsa-ucm module, but it's called with
a device name as a parameter. So if I have one USB headphone and one
USB mic, this module will be called twice. It's not clear to me then
how the virtual device would be handled, and how this is different
from inserting all the code in module-alsa-card as you did it in your
previous version?
- can you explain why you set the verb using the hook
PA_CORE_HOOK_SINK_INPUT_NEW, with priority PA_HOOK_EARLY+15. There are
other audio-policy related modules that may use different hooks, such
as PA_CORE_HOOK_SINK_INPUT_PUT. I would think you want to set the verb
at the UCM level after all this logic has made decisions, at the last
possible moment before data start flowing.
- how do we make use of modifiers?
- is there a better way to detect that UCM is supported, instead of
having a #define in module-alsa-card.c?

I realize I have more questions than suggestions, this is a good start anyway...

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