From 28855d2ac349b3fbb285c38493429dd1aa503523 Mon Sep 17 00:00:00 2001 From: Jani Nikula Date: Mon, 27 Oct 2014 16:27:00 +0200 Subject: [PATCH] drm/i915/audio: add DOC comment describing HDA over HDMI/DP v2: include the section in the drm docbook. Signed-off-by: Jani Nikula Reviewed-by: Rodrigo Vivi Signed-off-by: Daniel Vetter --- Documentation/DocBook/drm.tmpl | 5 +++++ drivers/gpu/drm/i915/intel_audio.c | 21 +++++++++++++++++++++ 2 files changed, 26 insertions(+) diff --git a/Documentation/DocBook/drm.tmpl b/Documentation/DocBook/drm.tmpl index f6a9d7b21380..01b8ca5f1a3d 100644 --- a/Documentation/DocBook/drm.tmpl +++ b/Documentation/DocBook/drm.tmpl @@ -3854,6 +3854,11 @@ int num_ioctls; probing, so those sections fully apply. + + High Definition Audio +!Pdrivers/gpu/drm/i915/intel_audio.c High Definition Audio over HDMI and Display Port +!Idrivers/gpu/drm/i915/intel_audio.c + DPIO !Pdrivers/gpu/drm/i915/i915_reg.h DPIO diff --git a/drivers/gpu/drm/i915/intel_audio.c b/drivers/gpu/drm/i915/intel_audio.c index 9181b85d86c4..44c49dfe1096 100644 --- a/drivers/gpu/drm/i915/intel_audio.c +++ b/drivers/gpu/drm/i915/intel_audio.c @@ -28,6 +28,27 @@ #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; -- 2.30.2