[alsa-devel] link between HDMI ELD and PCM devices

Stephen Warren swarren at nvidia.com
Wed Sep 21 01:33:45 CEST 2011

Pierre-Louis Bossart wrote at Tuesday, September 20, 2011 5:13 PM:
> Hi,
> I've been trying for some time to expose the HDMI ELD information in a
> new control. The problem I am facing with the HDMI/HDA code is that the
> ELD is linked to an output pin, and I can't find an elegant way to link
> this output pin with a PCM device number to be used by my control. For a
> single output, I could hard-code something but it would probably not
> work with multiple monitors handled by recent hardware.
> There is some existing code such as pin_nid_to_pin_index() in
> patch_hdmi.c, but I can't figure out what this pin_idx is, and how to
> find the related PCM device number.
> Any suggestions?

That function simply returns the index into the array spec->pins[] that
refers to that pin NID.

Judging by hinfo_to_pin_index() (e.g. used near the start ofhdmi_pcm_open),
that same index is valid  for spec->pcm_rec[] too, which I assume will
give you access to what you want, possibly through the .stream[0] field.


More information about the Alsa-devel mailing list