[Intel-gfx] [PATCH v2] drm/i915: Limit audio CDCLK>=2*BCLK constraint back to GLK only

[Takashi Iwai]

On Tue, 10 Mar 2020 19:25:22 +0100,
Ville Syrjälä wrote:
> 
> On Tue, Mar 10, 2020 at 07:18:58PM +0200, Kai Vehmanen wrote:
> > One problematic scenario that this doesn't cover:
> >  - a single display is used (at low cdclk), and 
> >  - audio block goes to runtime suspend while display stays up. 
> > 
> > Upon resume (for e.g. UI notification sound), audio will initialize the 
> > HDA bus and call get_power() on i915, even if the notification goes to 
> > internal speaker. A modeset at this point is potentially very annoying.
> 
> :( That seems much harder to deal with.

I guess it doesn't happen -- at least with the legacy HD-audio and the
recent chip, if I understand correctly.  When the stream is on the
analog codec, the HDMI codec is kept closed / runtime-resumed.  And
the additional get_power() in the controller side is done only for
HSW/BDW (where the HDA-bus is dedicated to HDMI).


Takashi