[vm-dev] Linux ALSA sound bug

[gromko]

It is a known problem.

Colin Guthrie wrote: "Yeah, this simply wont work with pulse in it's current
form, nor with other 
ALSA plugins for handlings certain things slightly out of the ordinary. 

The snd_async_add_pcm_handler() is not considered part of the "Safe" alsa
API. 

Lennart recently wrote a good guide about this: 
http://0pointer.de/blog/projects/guide-to-sound-apis.html

>From the section: 
"You want to know more about the safe ALSA subset?" 

"Do not use "async handlers", e.g. via snd_async_add_pcm_handler() and
friends. 
Asynchronous handlers are implemented using POSIX signals, which is a very 
questionable use of them, especially from libraries and plugins. Even when
you 
don't want to limit yourself to the safe ALSA subset it is highly
recommended 
not to use this functionality."

Disable PulseAudio or to write a plugin "vm-sound-PA" for works with
PulseAudio 
(use this example:
http://0pointer.de/lennart/projects/pulseaudio/doxygen/examples.html )


Bert Freudenberg wrote:
> 
>  
> Whenever I try to play a sound in Etoys on Fedora 10, the VM logs a  
> notice:
> 
> soundStart: snd_add_pcm_handler: Function not implemented
> 
> This has been reported a couple of times but did not make it to this  
> list yet, apparently:
> 
> 	http://tinyurl.com/c4kmta
> 
> A workaround is to force using OSS instead of ALSA using the -vm-sound- 
> OSS option.
> 
> I filed this at
> 
> http://bugs.squeak.org/view.php?id=7328
> 
> (wondered why it was auto-assigned to Tim - maybe Dave would be a  
> better taker now?)
> 
> - Bert -
> 
> 
> 

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