[alsa-devel] dsnoop issues

Jaroslav Kysela perex at suse.cz
Fri Apr 27 14:37:50 CEST 2007

On Fri, 27 Apr 2007, Gordon Miller wrote:

> Hi
> All my snd_pcm_readi calls return too few frames. Also when I switch to 
> stereo, the sound is muted. I cannot change this by adjusting period & 
> buffer sizes. dsnoop is enabled by default. The documentation for 
> snd_pcm_readi says that the only way that the frame count can be short 
> is because of a signal or xrun. Well this clearly isn't the case.
> I think that direct snoop is the cause of this. Are there any remedies ? 
> because I am roundly SICK of being told that my application must be 
> wrong "because everyone else's works". I have spent the last 3 weeks 
> debugging an app - that always worked properly - because of the faulty 
> dsnoop implementation.
> It is abundantly clear that dsnoop is far from ready for use, but I am 
> prepared to put some work into this.
> Whose idea was it to enable dsnoop by default, when it doesn't even work 
> ? I was quite happy with OSS. Changing everything to be alsa entailed a 
> lot of work, and I am beginning to think it was a complete waste of my time.
> ICE1712, kernel, alsa 1.0.14rc1

Send us a clear example which configuration does not work as you expect. 
We need:

a) simple test tool
b) reproduce error with arecord
c) debug output from snd_pcm_dump() before / while you read samples

It might be that it's no dsnoop fault, but some other plugin on way 
screw samples / stream position.

Your e-mail gives us nothing than "Houston, we have a problem". So it's 
almost useless.


Jaroslav Kysela <perex at suse.cz>
Linux Kernel Sound Maintainer
ALSA Project, SUSE Labs

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