Re: [Intel-gfx] [PATCH 1/2] drm/i915/display: optimize DP 2.0 sdp split update config

[Jani Nikula <jani.nikula@linux.intel.com>]

On Fri, 04 Aug 2023, Vinod Govindapillai <vinod.govindapillai@intel.com> wrote:
> Optimize DP 2 SDP split config update so that DP-MST code
> path can be supported as well.

What's the optimization?

>
> Signed-off-by: Vinod Govindapillai <vinod.govindapillai@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_audio.c   |  6 +++---
>  drivers/gpu/drm/i915/display/intel_audio.h   |  3 +--
>  drivers/gpu/drm/i915/display/intel_ddi.c     |  3 ---
>  drivers/gpu/drm/i915/display/intel_display.c |  3 +++
>  drivers/gpu/drm/i915/display/intel_dp.c      | 16 +++++++---------
>  drivers/gpu/drm/i915/display/intel_dp.h      |  2 ++
>  6 files changed, 16 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_audio.c b/drivers/gpu/drm/i915/display/intel_audio.c
> index 3d9c9b4f27f8..19605264a35c 100644
> --- a/drivers/gpu/drm/i915/display/intel_audio.c
> +++ b/drivers/gpu/drm/i915/display/intel_audio.c
> @@ -759,10 +759,10 @@ static void ibx_audio_codec_enable(struct intel_encoder *encoder,
>  	mutex_unlock(&i915->display.audio.mutex);
>  }
>  
> -void intel_audio_sdp_split_update(struct intel_encoder *encoder,
> -				  const struct intel_crtc_state *crtc_state)
> +void intel_audio_sdp_split_update(const struct intel_crtc_state *crtc_state)
>  {
> -	struct drm_i915_private *i915 = to_i915(encoder->base.dev);
> +	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
> +	struct drm_i915_private *i915 = to_i915(crtc->base.dev);
>  	enum transcoder trans = crtc_state->cpu_transcoder;
>  
>  	if (HAS_DP20(i915))
> diff --git a/drivers/gpu/drm/i915/display/intel_audio.h b/drivers/gpu/drm/i915/display/intel_audio.h
> index 07d034a981e9..9327954b801e 100644
> --- a/drivers/gpu/drm/i915/display/intel_audio.h
> +++ b/drivers/gpu/drm/i915/display/intel_audio.h
> @@ -29,7 +29,6 @@ void intel_audio_cdclk_change_pre(struct drm_i915_private *dev_priv);
>  void intel_audio_cdclk_change_post(struct drm_i915_private *dev_priv);
>  void intel_audio_init(struct drm_i915_private *dev_priv);
>  void intel_audio_deinit(struct drm_i915_private *dev_priv);
> -void intel_audio_sdp_split_update(struct intel_encoder *encoder,
> -				  const struct intel_crtc_state *crtc_state);
> +void intel_audio_sdp_split_update(const struct intel_crtc_state *crtc_state);
>  
>  #endif /* __INTEL_AUDIO_H__ */
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
> index 3cd2191fa794..542bc521669a 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> @@ -3247,9 +3247,6 @@ static void intel_enable_ddi(struct intel_atomic_state *state,
>  	if (!intel_crtc_is_bigjoiner_slave(crtc_state))
>  		intel_ddi_enable_transcoder_func(encoder, crtc_state);
>  
> -	/* Enable/Disable DP2.0 SDP split config before transcoder */
> -	intel_audio_sdp_split_update(encoder, crtc_state);
> -
>  	intel_enable_transcoder(crtc_state);
>  
>  	intel_crtc_vblank_on(crtc_state);
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> index 43cba98f7753..54afc559f522 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -402,6 +402,9 @@ void intel_enable_transcoder(const struct intel_crtc_state *new_crtc_state)
>  
>  	assert_planes_disabled(crtc);
>  
> +	/* Enable/Disable DP2.0 SDP split config before transcoder */
> +	intel_audio_sdp_split_update(new_crtc_state);

The call belongs in the encoder code. Search for "audio" in
intel_display.c; there's almost nothing.

> +
>  	/*
>  	 * A pipe without a PLL won't actually be able to drive bits from
>  	 * a plane.  On ILK+ the pipe PLLs are integrated, so we don't
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index 03675620e3ea..4a5be800715c 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -2232,17 +2232,15 @@ intel_dp_compute_output_format(struct intel_encoder *encoder,
>  	return ret;
>  }
>  
> -static void
> -intel_dp_audio_compute_config(struct intel_encoder *encoder,
> -			      struct intel_crtc_state *pipe_config,
> -			      struct drm_connector_state *conn_state)
> +void intel_dp_audio_compute_config(struct intel_crtc_state *pipe_config,
> +				   struct drm_connector_state *conn_state)
>  {
> -	struct drm_i915_private *i915 = to_i915(encoder->base.dev);
> +	struct intel_crtc *crtc = to_intel_crtc(pipe_config->uapi.crtc);
> +	struct drm_i915_private *i915 = to_i915(crtc->base.dev);
>  	struct drm_connector *connector = conn_state->connector;
>  
> -	pipe_config->sdp_split_enable =
> -		intel_dp_has_audio(encoder, conn_state) &&
> -		intel_dp_is_uhbr(pipe_config);
> +	pipe_config->sdp_split_enable = pipe_config->has_audio &&
> +					intel_dp_is_uhbr(pipe_config);

Hmmh, I don't get this.

I guess the neatest thing to do would be to have a single
intel_dp_audio_compute_config() that would do everything needed for DP
and DP MST, as well as call intel_audio_compute_config().

It think it's somewhat confusing that the compute config hooks call both
intel_audio_compute_config() and intel_dp_audio_compute_config(). Seems
like the latter should call the former.

BR,
Jani.



>  
>  	drm_dbg_kms(&i915->drm, "[CONNECTOR:%d:%s] SDP split enable: %s\n",
>  		    connector->base.id, connector->name,
> @@ -2334,7 +2332,7 @@ intel_dp_compute_config(struct intel_encoder *encoder,
>  		adjusted_mode->crtc_clock /= n;
>  	}
>  
> -	intel_dp_audio_compute_config(encoder, pipe_config, conn_state);
> +	intel_dp_audio_compute_config(pipe_config, conn_state);
>  
>  	intel_link_compute_m_n(output_bpp,
>  			       pipe_config->lane_count,
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.h b/drivers/gpu/drm/i915/display/intel_dp.h
> index 22099de3ca45..1a73820204ae 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.h
> +++ b/drivers/gpu/drm/i915/display/intel_dp.h
> @@ -65,6 +65,8 @@ int intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
>  				struct link_config_limits *limits,
>  				int timeslots,
>  				bool recompute_pipe_bpp);
> +void intel_dp_audio_compute_config(struct intel_crtc_state *pipe_config,
> +				   struct drm_connector_state *conn_state);
>  bool intel_dp_has_hdmi_sink(struct intel_dp *intel_dp);
>  bool intel_dp_is_edp(struct intel_dp *intel_dp);
>  bool intel_dp_is_uhbr(const struct intel_crtc_state *crtc_state);

-- 
Jani Nikula, Intel Open Source Graphics Center