drm/i915/audio: add DOC comment describing HDA over HDMI/DP

	  probing, so those sections fully apply.

        </para>

      </sect2>

      <sect2>

	<title>High Definition Audio</title>

!Pdrivers/gpu/drm/i915/intel_audio.c High Definition Audio over HDMI and Display Port

!Idrivers/gpu/drm/i915/intel_audio.c

      </sect2>

      <sect2>

        <title>DPIO</title>

!Pdrivers/gpu/drm/i915/i915_reg.h DPIO

#include "intel_drv.h"

#include "i915_drv.h"

/**

 * DOC: High Definition Audio over HDMI and Display Port

 *

 * The graphics and audio drivers together support High Definition Audio over

 * HDMI and Display Port. The audio programming sequences are divided into audio

 * codec and controller enable and disable sequences. The graphics driver

 * handles the audio codec sequences, while the audio driver handles the audio

 * controller sequences.

 *

 * The disable sequences must be performed before disabling the transcoder or

 * port. The enable sequences may only be performed after enabling the

 * transcoder and port, and after completed link training.

 *

 * The codec and controller sequences could be done either parallel or serial,

 * but generally the ELDV/PD change in the codec sequence indicates to the audio

 * driver that the controller sequence should start. Indeed, most of the

 * co-operation between the graphics and audio drivers is handled via audio

 * related registers. (The notable exception is the power management, not

 * covered here.)

 */

static const struct {

	int clock;

	u32 config;