# Alsa problem

**URL:** <https://www.ruby-forum.com/t/alsa-problem/242079>\
**Category:** GNU Radio\
**Created:** [May 25, 2015, 12:17pm UTC](https://www.ruby-forum.com/t/alsa-problem/242079 "2015-05-25T12:17:01Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Detlef\_R](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/58f4c7/32.png) [@Detlef\_R](https://www.ruby-forum.com/u/Detlef_R)\
**Post date:** [May 25, 2015, 12:17pm UTC](https://www.ruby-forum.com/t/alsa-problem/242079/1 "2015-05-25T12:17:01Z")

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Hi together,

i am using grc 3.7.6.1. The system is odroid with ubuntu 14. I tested  
the alsa system with aplay and the sound works.

When i start my project on odroid i get the following error message. On  
my desktop pc with grc 3.7.2.1 / ubuntu 14 the grc alsa works.

INFO: Audio sink arch: alsa  
ERROR: [default]: snd\_pcm\_hw\_params failed: Invalid argument  
Traceback (most recent call last):  
File “/home/odroid/gr-rds-master\_rds2/apps/rds\_rx.py”, line 421, in  
  
tb.Start(True)  
File  
“/usr/local/lib/python2.7/dist-packages/grc\_gnuradio/wxgui/top\_block\_gui.py”,  
line 73, in Start  
self.start()  
File  
“/usr/local/lib/python2.7/dist-packages/gnuradio/gr/top\_block.py”, line  
106, in start  
top\_block\_start\_unlocked(self.\_impl, max\_noutput\_items)  
File  
“/usr/local/lib/python2.7/dist-packages/gnuradio/gr/runtime\_swig.py”,  
line 4742, in top\_block\_start\_unlocked  
return \_runtime\_swig.top\_block\_start\_unlocked(\*args, \*\*kwargs)  
RuntimeError: check topology failed on audio\_alsa\_sink(54) using  
ninputs=2, noutputs=0

Andy ideas ? Thanks in advance.

cheers,  
Andy

---

<div class="post-metadata">

**Author:** ![andreas\_l](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/7bcc69/32.png) [@andreas\_l](https://www.ruby-forum.com/u/andreas_l)\
**Post date:** [May 25, 2015, 5:07pm UTC](https://www.ruby-forum.com/t/alsa-problem/242079/2 "2015-05-25T17:07:21Z")

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On Mon, May 25, 2015 at 6:15 AM, Andreas L.  
[removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
wrote:

> ERROR: [default]: snd\_pcm\_hw\_params failed: Invalid argument  
> top\_block\_start\_unlocked(self.\_impl, max\_noutput\_items)  
> cheers,  
> Andy

It would be helpful here to see the flowgraph you’re working on. The  
error  
is related to the blocks and how you connected them up. The audio sink,  
in  
this case, is having a problem with the input connections you’re giving  
it.

Tom