[Sound-open-firmware] HDMI audio not working on Up^2

[Liam Girdwood]

On Fri, 2019-03-22 at 09:49 -0500, Pierre-Louis Bossart wrote:
> > I tried to test HDMI audio on Up^2 and hdac_hdmi_set_hw_params() is
> > failing with -ENODEV because no port is assigned. Some very light
> > analysis and debugging showed, that hdac_hdmi_pcm_open() hasn't
> > been called, but it might wrong. Are there any non-trivial
> > requirements to use HDMI audio on Up^2? Can it be, that my monitor
> > or my cable aren't good enough?
> 
> You need to set the PortN-PinM mixers, otherwise the hw_params will 
> fail. It's super painful and I don't know why it's needed but that's 
> what it is for now.
> I typically look for the dmesg, find out which port is not disconnected, 
> and usually set Port6Pin0 to 1, then use hw:0,1 to get things to play.
> I don't have the hardware with me so can't provide better advice.
> Also please use the dapm graph tool to make use everything is setup 
> correctly.

Guennadi, could you document this on sof-docs with a paragraph and your example
config / changes. Nothing long needed, just enough to point others in the
correct direction.

Thanks

Liam