[alsa-devel] Passing audio info from HDMI EDID beside speaker allocation

Pierre-Louis Bossart pierre-louis.bossart at linux.intel.com
Wed Oct 24 00:56:33 CEST 2012

>>> In the case of HD-audio, it's passed via the normal IEC958 status bits
>>> controls separately.  ELD itself is exposed as a byte array in a
>>> control element, but it's read-only.
>> Thanks for the reply. Couple more questions
>> 1. Is kcontrol "ELD" being read directly by application or there is
>> ALSA library API to parse the information.
> Nothing so far.  It's just a raw data.
>> 2. Also, I see you submit this patch [PATCH 3/3] ELD proc interface for
>> HDMI sinks in 2008. I presume it's just for information purpose. You
>> still expect application to query for HDMI sink capability through
>> "ELD" kcontrol. Am I correct?
> It's not prohibited for apps to parse the proc interface but it's not
> guaranteed to be stable :)  So yes, parsing ELD manually would be a
> safer way.

I wrote some code to parse the ELD kcontrol to enable passthrough if AC3 
is supported by the receiver, I believe it's been integrated by Arun in 
a branch of PulseAudio. It's probably 1 year old now..

More information about the Alsa-devel mailing list