[alsa-devel] HDMI audio: TV vs. codec supported sample rates

[Takashi Iwai]

At Thu, 5 Aug 2010 12:49:07 +0300,
Anssi Hannula wrote:
> 
> Anssi Hannula kirjoitti tiistai, 3. elokuuta 2010 20:39:20:
> > Stephen Warren kirjoitti tiistai, 3. elokuuta 2010 19:20:24:
> > > I don't see anything in patch_intelhdmi.c that relates to sample rate
> > > support at all. However, I see that patch_nvhdmi.c contains e.g.:
> > > 
> > > static struct hda_pcm_stream nvhdmi_pcm_digital_playback_8ch_89 = {
> > > 
> > >         .substreams = 1,
> > >         .channels_min = 2,
> > >         .rates = SUPPORTED_RATES,
> > > 
> > > Should .rates not be initialized here,
> > 
> > When .rates is not initialized, they are automatically read from the codec,
> > i.e. exactly the values you referenced above from
> > "/proc/asound/card1/codec#1".
> > 
> > The values seem to differ (32000 vs 22050 is reported as supported),
> > though. If the codec reported values are wrong, the .rates should be kept.
> > Otherwise the rates set in .rates should be fixed or the override just
> > removed.
> 
> As AFAICS HDMI specification allows 32000Hz but not 22050Hz, I'd say it is 
> likely that the override is wrong and the codec reported rates are right.
> 
> (my receiver doesn't support 32000Hz so I can't confirm).

So, the codec reports correct values based on EDID?
IIRC, the static values there were needed for old Nvidia codecs that
don't give the actual values.  Maybe newer chips work correctly.
If so, rates, maxbps and formats in *_89 (also *_7x, too?) can be
removed, indeed.

Can any confirm?


thanks,

Takashi