[alsa-devel] HDMI codec, way forward?

[Jani Nikula]

On Tue, 20 Oct 2015, Vinod Koul <vinod.koul at intel.com> wrote:
> On Tue, Oct 20, 2015 at 09:08:00AM +0100, Russell King - ARM Linux wrote:
>> > > Currently i915/audio component works as you described.  The audio is
>> > > optional and HDMI graphics works without audio, while HDMI HD-audio
>> > > mandates i915 graphics.
>> > 
>> > Right, but we also add additional interface on top of this to allow
>> > things like ensuring display is on when audio wants to run and now
>> > notification for events.
>> > 
>> > I don't see a reason why this can be used as single interface to bind as
>> > well as talk to display from various components, unless I missed obvious
>> > which prevent us from doing this in non i915 cases...
>> 
>> Maybe I can comment more specifically if I saw the code.  Right now all
>> I'm aware of is this idea without any code, and I don't like it.
>
> Ok, i will be post my patches tomorrow. FWIW uses interface in
> sound/hda/hdac_i915.c for display power up/down

Side note, some of the Intel HD audio controller registers are in a
power domain controlled by i915. The audio drivers needs to do power
get/put, otherwise the audio driver loses its marbles when i915 switches
off power. OTOH audio needs to be a good citizen so i915 can reach low
power states.

Just a shout from the back, unsure if this is relevant at this point...


BR,
Jani.



-- 
Jani Nikula, Intel Open Source Technology Center