[Intel-gfx] [PATCH v5] drm/i915: pass ELD to HDMI/DP audio driver

[Wu Fengguang]

(snip)
> > > > > And I'm not sure whether HDMI audio is played
> > > > > while DPMS is off.  I haven't tested it.
> > > > 
> > > > It will go silence on DPMS. I noticed this while doing long term HDMI
> > > > audio playback tests.  This should better be fixed in future on the
> > > > graphics side.
> > > 
> > > Hm, but I wonder what could be done alternatively.
> > > Hopefully there is a register for video-only control...
> > 
> > There may be some mode that can keep video off while still keep
> > minimal signals to play HDMI sound?
> 
> Let's hope :)

Looks very possible, here is the clue of hardware support:

        TRANS_DP_CTL - Transcoder DisplayPort Control

        bit 26: Transcoder DP Audio Only Mode

Thanks,
Fengguang