[alsa-devel] [PATCH v3 03/10] ASoC: hdac_hda: add support for HDMI/DP as a HDA codec

[Kai Vehmanen]

Hi,

On Tue, 10 Sep 2019, Pierre-Louis Bossart wrote:

> On 9/10/19 1:29 PM, Kai Vehmanen wrote:
> > +	.id = HDAC_HDMI_0_DAI_ID,
> > +	.name = "intel-hdmi-hifi1",
> > +	.ops = &hdac_hda_dai_ops,
> > +	.playback = {
> > +		.stream_name    = "hifi1",
> > +		.channels_min   = 1,
> > +		.channels_max   = 16,
> 
> IIRC HDMI only deals with 8ch?

good catch. I had just copied these from hdac-hda.c. HDMI2.0 actually 
bumped this from 8 to 32 channels.

The constraints remain pretty wide and unsupported configurations will be 
caught at runtime in PCM open in patch_hdmi.c where requested channel 
count is compared to ELD information.

In comparison, the hdac-hdmi does query and add some static constraints 
with snd_hdac_query_supported_pcm(), but e.g. for channels it just sets 
min/max to 2.

> > +		.rates          = SNDRV_PCM_RATE_8000_192000,
> 
> And frequencies above 32kHz

Ack, will fix. I'll probably keep the maximum at 192kHz. HDMI2.0/DP1.4 in 
fact bumped maximum to 1536kHz, but practically that is probably for 
8x192kHz (or 32x48kHz) audio.

Br, Kai