Re: [RFC 0/4] ASoC: Add HDA HDMI codec driver

[Russell King - ARM Linux <linux@arm.linux.org.uk>]

On Fri, Oct 09, 2015 at 01:28:45PM +0100, Vinod Koul wrote:
> Yes, this patch series attempts to add yet another HDMI driver to
> ASoC. This codec appears as HDA codec over HDA link. Although
> the codec reside in display we have a HDA link from audio block
> to this codec. The communication to codec is over HDA link
> 
> Thanks to i915 component infrastructure, we do not need to worry
> about keeping the codec on, this is done by i915 for us.
> 
> Based on discussion with Mark here at ELCE and other attempts by
> various folks on HDMI, I wanted to show on list the stuff we have
> done and discuss and try to see how we converge various attempts
> 
> The driver here only supports stereo and doesn't do multichannel
> just yet, will add later once we converge here. The support for
> using i915 component notification by David will be added later
> on.

I notice that you don't limit the capabilities of the ASoC device to
the capabilities of the HDMI sink - is that an intentional design
decision, or is it handled some other way?

I think that's the "interesting" part of HDMI - how should audio find
out the capabilities on the HDMI sink, and that's the area which people
have been struggling to design and come to some sort of concensus over.

I know HDA passes the ELD through hardware between the HDMI video and
HDMI audio side, which hides some of this with the existing ALSA PCI
HDA driver.

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