[PATCH v2] ALSA: hda/hdmi: add keep-alive support for ADL-P and DG2

[Takashi Iwai]

On Wed, 16 Feb 2022 18:24:05 +0100,
Kai Vehmanen wrote:
> 
> Implement HDA keep alive (KAE) support for Intel display codecs. When no
> audio stream is active, the display codec will provide a continuous clock
> and a valid but silent audio stream to any connected HDMI/DP receiver.
> Without this, upon starting a new playback stream, initial samples may be
> lost as many receivers require time to initialize for new clock.
> 
> This is a new feature in Intel AlderLake-P display codec implementation
> and replaces the Intel i915 silent-stream extension that has been used
> on older hardware. Main benefit of the new method is that codec no longer
> needs to be kept in D0 power state.
> 
> This patch depends on commit 112a87c48e83 ("drm/i915/display: program
> audio CDCLK-TS for keepalives").
> 
> Signed-off-by: Kai Vehmanen <kai.vehmanen at linux.intel.com>
> Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart at linux.intel.com>
> Reviewed-by: Jyri Sarha <jyri.sarha at intel.com>

Thanks, applied now with a minor coding-style fix the checkpatch
warned.


Takashi