[alsa-devel] [PATCH] ALSA: HDA: Add jack detection for HDMI

Stephen Warren swarren at nvidia.com
Tue May 17 18:00:51 CEST 2011

David Henningsson wrote at Tuesday, May 17, 2011 7:47 AM:
> Just as for headphones and microphone jacks, this patch adds reporting
> of HDMI jack status through the input layer.

Interesting. I was asked to look into this, but you beat me to it; thanks!

A couple questions though:

a) Is it possible to report more information alongside the plug events,
such as ELD/EDID content? Or, is the idea that the kernel sends a plug
event, and then user-space retrieves that information via some other
API? I don't think there's an API to retrieve ELD information at present
though right? Although certainly it'd make sense for that to be a 
completely separate patch.

b) We might discuss how to tie ALSA jacks/ports/PCMs to X displays in
some way, so that we can represent to the user which specific active
monitor is the one that supports audio (e.g. in a 2-head setup with both
monitors connected over HDMI, yet only 1 monitor supports audio).

I note that the ELD data contains a port_id field, which might be usable
for this purpose. Could this contain an xrandr value, or an NV-CTRL
(NVIDIA's proprietary control protocol) display ID, or something similar?


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