[alsa-devel] Still have choppy audio using 1.0.17

Gustavo da Silva Serra gustavo.serra at tet.com.br
Fri Jul 4 14:40:06 CEST 2008

I forgot a very important detail, when I can choose the output plugin 
(alsa or oss in Kaffeine, for example), only alsa has choppy audio. oss 
plugin works perfectly, only using kernel module emulation.

Gustavo da Silva Serra escreveu:
> I have tried to implement the solution you proposed. However I still 
> get choppy audio, just like before, otherwise the sound is clear.
> Basically I moved the timer to the cable struct, and updated the timer 
> function to update both playback and capture.
> I am sending the code attached so you can see if I implemented what 
> you suggested. The code is not very clean, nor completely functional, 
> as I never programmed to kernel before, and might cause kernel panic 
> when closing a stream.
> Any other suggestions?
> Thanks for the help and the attention.
> Takashi Iwai escreveu:
>> At Wed, 25 Jun 2008 08:24:33 -0300,
>> Gustavo da Silva Serra wrote:
>>> If I keep the difference between the playback and capture pointers 
>>> at one period, no choppy audio occurs. If the difference is 0, 2 or 
>>> 5 periods for example, choppy audio will always occur. Any ideas why?
>> Through a quick look at the code, it's likely the problem of the
>> timing of timer handlers for playback/capture streams.  In the current
>> code, the timer handlers are invoked individually.
>> One possible fix would be to force to synchronize the updates of both
>> directions instead of individual timers.  That is, share the same
>> timer for the connected streams so that the update order is
>> guaranteed.
>> Just my $0.02.
>> Takashi
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