Re: [virtio-dev] [PATCH] snd: Add virtio sound device specification

[Anton Yakovlev <anton.yakovlev@opensynergy.com>]

Hi Christophe,


On 28.11.2019 10:37, Christophe de Dinechin wrote:
> > On 22 Nov 2019, at 15:06, Anton Yakovlev <anton.yakovlev@opensynergy.com> wrote:
> >
> > On 22.11.2019 13:35, Mark Brown wrote:
> > > On Thu, Nov 21, 2019 at 01:57:51PM +0100, Anton Yakovlev wrote:
> > > > SNDRV_PCM_FORMAT_MPEG
> > > > SNDRV_PCM_FORMAT_GSM
> > > > SNDRV_PCM_FORMAT_G723_24
> > > > SNDRV_PCM_FORMAT_G723_24_1B
> > > > SNDRV_PCM_FORMAT_G723_40
> > > > SNDRV_PCM_FORMAT_G723_40_1B
> > > > Do we really need all of them? And I skipped endianess, but should we care
> > > > about it as well?
> > > The compressed audio formats I quoted above (and possibly some others)
> > > are mostly redundant and better handled through something like the ALSA
> > > compressed audio interface but that's definitely a separate thing with
> > > different requirements.
> >
> > Then let's include all except these.
>
> Is the intent that any virtio device has to support all the same formats?
>
> If Iâm talking to a hardware decoder, then a compressed format makes sense
> (there is no point in decompressing in software if the deviceâs very purpose
> is to do it in hardware). But then, maybe it supports one format but not another.
>
> So it looks to me like all the formats should be part of the spec, and some
> device capabilities should indicate which ones the device accepts.

We discussed only PCM-related things. Compressed offload could be as a feature
with its own configuration layout, format definitions, request types, maybe
virtqueue(s) and so on.


> Thanks
> Christophe
>
> > --
> > Anton Yakovlev
> > Senior Software Engineer
> >
> > OpenSynergy GmbH
> > Rotherstr. 20, 10245 Berlin
> >
> > Phone: +49 30 60 98 54 0
> > E-Mail: anton.yakovlev@opensynergy.com
> >
> >
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--
Anton Yakovlev
Senior Software Engineer

OpenSynergy GmbH
Rotherstr. 20, 10245 Berlin

Phone: +49 30 60 98 54 0
E-Mail: anton.yakovlev@opensynergy.com

www.opensynergy.com

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