[Vm-dev] pulse audio default is not suitable for PI package

K K Subbu kksubbu.ml at gmail.com
Wed Apr 22 18:34:22 UTC 2020

On 22/04/20 8:19 PM, Tobias Pape wrote:
> Squeak does not  "use" OSS as such; it has several sound plugins; Alsa, Pulse, OSS, NAS etc.
> It probes which plugins are available.

I was using general terms. Mea culpa. Yes, it is the plugins which use 
the APIs.

> To be quite clear:
> 	Squeak Can use  Pulse natively.
> no padsp necessary.True, but that is true only if the pulse driver is chosen by the VM.

> However, we have to see if the vm does the right thing if a plugin_can_  load but the environment
> does not fit > In this case: vm-sound-oss loads but /dev/dsp0 is not there. in this 
case, continue trying or so…

That is because OSS PCM devices are emulated these days. Its pcm device 
path can differ from distro to distro and even within a distro.

I would try:
    $ padsp squeak
    $ aoss squeak

as a workaround. Detecting failures in VM can be tricky. The OSS pcm 
device path can differ from distro to distro and even within a distro. 
Even if vm-sound-oss module loads successfully but the audio may be of 
poor quality. The code in VM can quickly become complex.

BTW, OSS was replaced in Linux by ALSA way back in 2002! Audio has 
advanced a lot since then (USB, BT, HD Audio, ..). ALSA supports OSS 
through kernel modules (snd-pcm-oss, for those with root permissions) or 
wrapper (aoss). It is specific to Linux while Pulse also works on 
Unix-like platforms, is network-ready, works with multiple back-ends 
like ALSA or Jack and supports OSS through padsp wrapper.

Regards .. Subbu

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