[bug/fix] Qubes + USB microphone

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Andrew B

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Oct 21, 2014, 1:54:22 PM10/21/14

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Hi,

I've been bothered for a while that USB microphones (e.g. attached to a webcam) do not work when the relevant USB controller is assigned to the target AppVM. Even more baffling is that ALSA detects the card just fine, and killing pulseaudio and relaunching it manually (without the extra Qubes stuff) also sees the card just fine, but then won't send sound output to Dom0.

I found the problem: The Qubes PulseAudio config file at /etc/pulse/qubes-default.pa does not load the 'module-udev-detect' module. Add the line, "load-module module-udev-detect" after "load-module module-vchan-sink" to that file (AFAIK it could be anywhere, but this is where I put it). Make this change to the relevant TemplateVM so it's persistent. Now everything should work normally.

Marek: is there a specific reason module-udev-detect is not loaded by default, or is it just a bug?
Andrew

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Marek Marczykowski-Górecki

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Oct 21, 2014, 6:26:39 PM10/21/14

to Andrew B, qubes-users

Basically to speed up the startup and lower memory footprint. The same reason
as for a bunch of other pulseaudio modules (bluetooth, network discovery
protocols etc).

You have documented it here:
https://wiki.qubes-os.org/wiki/ExternalAudio

--
Best Regards,
Marek Marczykowski-Górecki
Invisible Things Lab
A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?