Re: [Gumstix-users] audio from usb mic on verdex board

[hughsw <hs...@ho...>]

Thanks for the starting pointer Rasmus.  I've been trying to get
aplay/arecord to work on my brand-new verdex xm4.

I've set up the oe toolchain on my Ubuntu 7.10 system and am using the
latest SVN sources.  I'm building packages using uclibc because I believe I
need to do that until I install a new glibc-based image.  I have my own
user.collection/conf/machine/gumstix-custom-verdex.conf which leaves out
some unnecessary machine options.  I do 'bitbake -c rebuild
task-base-gumstix' and 'bitbake -c rebuild gumstix-basic-image'.  Under
./tmp I found a version of aplay in the alsa-utils and copied the package to
the gumstix and used ipkg to install it.   But when I run aplay or arecord,
I get a segmentation fault.  

I was able to install ldd and have it successfully examine /usr/bin/aplay,
so some things in my oe toolchain are working.  I made sure all the
necessary libraries for aplay/arecord were available.  Still a seg fault. 
Guessing it's a kernel-modules issue.  I copied various kernel modules
related to USB and sound onto the gumstix, and some of them would even load
with modprobe, but others refused to load even though the blah.ko file is
right there (other version mismatches?). Still a seg fault.  I need help.

I would like to be able to do audio in and out through USB devices using the
ALSA api.  Specifically I will connect USB audio devices like headset,
microphone, speakers.  As I said, /proc/bus/usb/devices shows the audio
devices when I connect them to the console-vx USB port, so the kernel is
doing some USB stuff right.

I think the best solution would be to have conf, images and tasks in
user.collections that build the root image I need, with all the necessary
libraries, and all the correct module dependencies getting automatically
built by bitbake and loaded at boot time.  I'll switch to using glibc as
that appears to be the recommended solution going forward.

Here are my questions for the experts:
- How do I figure out which modules and libraries are necessary for the alsa
libraries and utilities to run?
- How do I modifiy my own user.collection/packages/{tasks,images,?} so as to
get everything into the image.  This is where I'm most lost in terms of
figuring out what to edit and how to get dependencies correctly tracked
down.
- When I make a change in a *.bb file, how do I get the dependent things to
rebuild?
- Relatedly, what's the recommended way to force a clean build of a
collection?
- What else have I overlooked?

Thanks in advance.
-Hugh



Rasmus Kjeldsen wrote:
> 
> Hi Hugh
> 
> Try "arecord". arecord is in the buildroot (dont kown about oe).
> 
> Cheers
> Rasmus Friis Kjeldsen
> 
> 2008/2/28, Hugh Secker-Walker <hs...@ho...>:
>>
>> Hi All,
>>
>> I just got a verdex starter pack.  Plugged it into my router, fired it
>> up and logged in via ssh.  Tried browsing to it too, but the web server
>> was not working.  Figured out the SeverName problem with the help of
>> this list's archives... and now the http server is working.
>>
>> I've plugged in a USB mic, and info about it appears in
>> /proc/bus/usb/devices
>>
>> The question is, how do I access the USB mic from C code I will write in
>> order to record audio wavedata?  Do I write to the ALSA Api or something
>> different?  Can someone point me to a project or code that will record
>> from the USB mic?  Any advice or pointers about USB-based audio would be
>> welcomed.  BTW, I've installed the OE toolchain on an Ubuntu box and
>> have, apparently, built a JFFS2 image.  I also have an audiostix 2, but
>> I really need USB mic access.
>>
>> TIA,
>> -Hugh
> 
> 

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