https://bugs.freedesktop.org/show_bug.cgi?id=67550
--- Comment #5 from Andre Heider a.heider@gmail.com --- (In reply to comment #4)
(In reply to comment #0)
#2, without xorg.conf The receiver sends its own EDID block, so I can extend via xrandr without turning on the projector. But the projector is turned off in most cases, so is there a way to disable a display output but keep the HDMI audio output? (as a workaround for #1)
Nope, unfortunately not. It's by HDMI design, the audio signal is mixed into the vertical and horizontal blank periods of the video signal -> so if you don't have a video signal you don't have audio also.
As a workaround you could try to setup a second X server or framebuffer or something like that (kms console?) on the HDMI output to just get a video signal on it.
Okay, thanks for clearing that up.
Another workaround would be HDMI multichannel audio for radeon :) Does AMD have any plans to implement that?