Hi,

On Tue, Mar 10, 2020 at 12:50:56PM +0000, Mark Brown wrote:

On Mon, Mar 09, 2020 at 05:05:06PM -0500, Pierre-Louis Bossart wrote:

...

To get a better picture of the directions, reviewers are invited to take a look at the in-depth documentation written by Guennadi since the initial patches were shared. This documentation was reviewed by Liam and me and is really required to understand the concepts:

...

https://thesofproject.github.io/latest/developer_guides/virtualization/virtu...

How does this relate to the virtio audio spec that's currently under review?

The spec under discussion is only for simple audio virtualisation with fixed roles and topologies. With our approach guests get access to advanced DSP capabilities. The virtualisation approach under discussion can be a fallback for cases when no DSP has been detected on the host.

It looks to be doing something much lower level than that. I am concerned that this looks to be exposing DPCM as a virtio ABI, we're trying to replace it as an internal API never mind ABI.

You mean that our approach works at the widget level, which is a part of the DPCM API? Well there is a translation layer between our ABI and DPCM. And by virtue of the same argument don't we already have DPCM as an ABI on the opposite side of SOF - in its IPC ABI? Largely this virtualisation approach doesn't add new interfaces, it re-uses the SOF IPC ABI, which is also one of its advantages.

Thanks Guennadi