[alsa-devel] Attempts to get a USB device operating.

Tom Watson sdc695 at yahoo.com
Sun Mar 29 07:15:53 CEST 2009

I've got a (real) cheap usb sound "card" that partially works with ALSA.  I can get the microphone input to respond by fiddling with some of the switches, but I have been unable to ge the output functions to work (produce output) at all.  The "indicating" (power) light flashes, but I get no sound.  Another thing that is weird is that while the litle box has SPDIF connections (both in and out) I don't see them on the mixer panel.  Any clues would be appreciated.  I have done the upload using 'alsa-info' with the defaults.  Some brief details:
lsusb yields:
Bus 001 Device 034: ID 0d8c:0102 C-Media Electronics, Inc.

The output mixer panel shows two outputs (speakers),
The input mixer shows three inputs (2xPCM, 1 Mic).
The switches mixer shows a PCM capture source and a single PCM switch.

Are there any experiments I can do to help out in the investigation?  I'm only using aplay/arecord in doing this test, just to make things 'easy' to diagnose.

Thanks for the help.

Tom Watson
tsw at johana.com


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