RomanG
Posts: 41
Joined: Fri Aug 17, 2012 11:56 am
Location: Ottawa, Canada

Servoblaster interfering with ALSA?

Sun Feb 03, 2013 4:34 pm

I have experienced strange issue.
After recent system upgrade to:

Code: Select all

uname -a
Linux RPi 3.6.11+ #362 PREEMPT Tue Jan 22 14:52:21 GMT 2013 armv6l GNU/Linux
my audio (through an on-board audio jack) stopped working. There would be just static, even if nothing is playing, and when I would attempt to play a wav file through aplay or use espeak, there would be only high pitch pulsation (something between a fax machine signal and dolphin whistling).

I flashed back older backup image:

Code: Select all

uname -a
Linux RPi 3.2.27+ #250 PREEMPT Thu Oct 18 19:03:02 BST 2012 armv6l GNU/Linux
and everything worked fine.

I searched forums and found some suggestions (i.e. uninstalling pulseaudio...etc) but nothing solved the problem.

Few days ago I was playing again with the servoblaster and had left one of the servos connected to the GPIO.
Today, when I run espeak the servo started to turn (continuous rotation modified servo).
Hmm...., that was weird.

So I unloaded servoblaster module and suddenly both, the aplay as well as espeak work fine.
As soon as I load servoblaster module back, I can hear the static in my earphones and when attempt to play a wav file or use espeak, I gett that high pitch pulsation again.

Unloading servoblaster module brings audio back.

Any suggestions highly appreciated!

thanks,
Roman

RomanG
Posts: 41
Joined: Fri Aug 17, 2012 11:56 am
Location: Ottawa, Canada

Re: Servoblaster interfering with ALSA?

Mon Feb 04, 2013 4:52 pm

"Mystery" solved. Some explanation here:
http://www.raspberrypi.org/phpBB3/viewt ... 52#p277252

Roman

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