Re: [very-RFC 0/8] TSN driver for the kernel

Henrik Austad
2016-06-14T20:38:22Z

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On Tue, Jun 14, 2016 at 08:26:15PM +0200, Richard Cochran wrote:
> On Tue, Jun 14, 2016 at 11:30:00AM +0200, Henrik Austad wrote:
> > So loop data from kernel -> userspace -> kernelspace and finally back to
> > userspace and the media application?
>
> Huh? I wonder where you got that idea. Let me show an example of
> what I mean.
>
> void listener()
> {
> int in = socket();
> int out = open("/dev/dsp");
> char buf[];
>
> while (1) {
> recv(in, buf, packetsize);
> write(out, buf + offset, datasize);
> }
> }
>
> See?

Where is your media-application in this? You only loop the audio from
network to the dsp, is the media-application attached to the dsp-device?

Whereas I want to do

aplay some_song.wav
or mplayer
or spotify
or ..

> > Yes, I know some audio apps "use networking", I can stream netradio, I can
> > use jack to connect devices using RTP and probably a whole lot of other
> > applications do similar things. However, AVB is more about using the
> > network as a virtual sound-card.
>
> That is news to me. I don't recall ever having seen AVB described
> like that before.
>
> > For the media application, it should not
> > have to care if the device it is using is a soudncard inside the box or a
> > set of AVB-capable speakers somewhere on the network.
>
> So you would like a remote listener to appear in the system as a local
> PCM audio sink? And a remote talker would be like a local media URL?
> Sounds unworkable to me, but even if you were to implement it, the
> logic would surely belong in alsa-lib and not in the kernel. Behind
> the enulated device, the library would run a loop like the example,
> above.
>
> In any case, your patches don't implement that sort of thing at all,
> do they?

Subject: [very-RFC 7/8] AVB ALSA - Add ALSA shim for TSN

Did you even bother to look?

--
Henrik Austad

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