[alsa-devel] snd_dummy on Centos - Redhat

Giovanni Maruzzelli gmaruzz.lists at gmail.com
Tue Sep 8 17:34:35 CEST 2009

On Tue, Sep 8, 2009 at 5:10 PM, Takashi Iwai<tiwai at suse.de> wrote:
> Don't pass '=', e.g.
>        # echo channels_max 3 > /proc/..../dummy_pcm

Thanks, with your hint I was able to write to the proc file.

I confirm that the Skype client works well if I put (writing to the
proc file, without modifying the driver source): buffer_bytes_max=1024
and period_bytes_max=512, and that it works bad if I do not write on
the /proc file.

It would be very very very nice if you add this proc interface (or
another method to alter those buffer and period values) also to the
non-debug build, so users can be able to use the standard distributed
prepackaged ALSA drivers, without resorting to editing source or

BTW: Would you mind to bump the MAX_PCM_SUBSTREAMS to 128? Currently
is 16, and is a cap to the substreams actually created, by a
configurable param default to 8. (people use routinely 20 concurrent
Skype clients, 40 substreams. But there is juice in modern servers to
have some more. 64 seems roomy enough [Skype client itself uses lot of

Thanks for all your efforts,


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