Re: [Intel-gfx] [PATCH 01/16] Revert "drm/i915/display: Disable audio, DRRS and PSR before planes"

["Souza, Jose" <jose.souza@intel.com>]

On Mon, 2021-09-13 at 17:44 +0300, Ville Syrjala wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> 
> Disabling planes in the middle of the modeset seuqnece does not make
> sense since userspace can anyway disable planes before the modeset
> even starts. So when the modeset seuqence starts the set of enabled
> planes is entirely arbitrary. Trying to sprinkle the plane disabling
> into the modeset sequence just means more randomness and potential
> for hard to reproduce bugs.

The patch being reverted did not changed anything about plane, it only disables audio and PSR before pipe is disabled in this case.
I have other pending patch handling cases were userspace still has pipe enabled but no planes enabled.

> 
> So it makes most sense to just disable all planes first so that the
> rest of the modeset sequence remains identical regardless of which
> planes happen to be enabled by userspace at the time.

This is not what specification ask us to do and for Alderlake-P not following it causes underruns.

BSpec: 49190

> 
> This reverts commit 84030adb9e27d202a66022488bf0349a8bd45213.
> 
> Cc: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>
> Cc: José Roberto de Souza <jose.souza@intel.com>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_ddi.c      | 30 +++++++------------
>  drivers/gpu/drm/i915/display/intel_display.c  | 24 ---------------
>  .../drm/i915/display/intel_display_types.h    |  4 ---
>  drivers/gpu/drm/i915/display/intel_dp_mst.c   | 14 ++-------
>  4 files changed, 13 insertions(+), 59 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
> index 23ef291f7b30..c1fd7cbb40e1 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> @@ -3164,6 +3164,12 @@ static void intel_disable_ddi_dp(struct intel_atomic_state *state,
>  
>  	intel_dp->link_trained = false;
>  
> +	if (old_crtc_state->has_audio)
> +		intel_audio_codec_disable(encoder,
> +					  old_crtc_state, old_conn_state);
> +
> +	intel_drrs_disable(intel_dp, old_crtc_state);
> +	intel_psr_disable(intel_dp, old_crtc_state);
>  	intel_edp_backlight_off(old_conn_state);
>  	/* Disable the decompression in DP Sink */
>  	intel_dp_sink_set_decompression_state(intel_dp, old_crtc_state,
> @@ -3181,6 +3187,10 @@ static void intel_disable_ddi_hdmi(struct intel_atomic_state *state,
>  	struct drm_i915_private *i915 = to_i915(encoder->base.dev);
>  	struct drm_connector *connector = old_conn_state->connector;
>  
> +	if (old_crtc_state->has_audio)
> +		intel_audio_codec_disable(encoder,
> +					  old_crtc_state, old_conn_state);
> +
>  	if (!intel_hdmi_handle_sink_scrambling(encoder, connector,
>  					       false, false))
>  		drm_dbg_kms(&i915->drm,
> @@ -3188,25 +3198,6 @@ static void intel_disable_ddi_hdmi(struct intel_atomic_state *state,
>  			    connector->base.id, connector->name);
>  }
>  
> -static void intel_pre_disable_ddi(struct intel_atomic_state *state,
> -				  struct intel_encoder *encoder,
> -				  const struct intel_crtc_state *old_crtc_state,
> -				  const struct drm_connector_state *old_conn_state)
> -{
> -	struct intel_dp *intel_dp;
> -
> -	if (old_crtc_state->has_audio)
> -		intel_audio_codec_disable(encoder, old_crtc_state,
> -					  old_conn_state);
> -
> -	if (intel_crtc_has_type(old_crtc_state, INTEL_OUTPUT_HDMI))
> -		return;
> -
> -	intel_dp = enc_to_intel_dp(encoder);
> -	intel_drrs_disable(intel_dp, old_crtc_state);
> -	intel_psr_disable(intel_dp, old_crtc_state);
> -}
> -
>  static void intel_disable_ddi(struct intel_atomic_state *state,
>  			      struct intel_encoder *encoder,
>  			      const struct intel_crtc_state *old_crtc_state,
> @@ -4541,7 +4532,6 @@ void intel_ddi_init(struct drm_i915_private *dev_priv, enum port port)
>  	encoder->enable = intel_enable_ddi;
>  	encoder->pre_pll_enable = intel_ddi_pre_pll_enable;
>  	encoder->pre_enable = intel_ddi_pre_enable;
> -	encoder->pre_disable = intel_pre_disable_ddi;
>  	encoder->disable = intel_disable_ddi;
>  	encoder->post_disable = intel_ddi_post_disable;
>  	encoder->update_pipe = intel_ddi_update_pipe;
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> index a7ca38613f89..cd150512d275 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -2723,28 +2723,6 @@ static void intel_encoders_enable(struct intel_atomic_state *state,
>  	}
>  }
>  
> -static void intel_encoders_pre_disable(struct intel_atomic_state *state,
> -				       struct intel_crtc *crtc)
> -{
> -	const struct intel_crtc_state *old_crtc_state =
> -		intel_atomic_get_old_crtc_state(state, crtc);
> -	const struct drm_connector_state *old_conn_state;
> -	struct drm_connector *conn;
> -	int i;
> -
> -	for_each_old_connector_in_state(&state->base, conn, old_conn_state, i) {
> -		struct intel_encoder *encoder =
> -			to_intel_encoder(old_conn_state->best_encoder);
> -
> -		if (old_conn_state->crtc != &crtc->base)
> -			continue;
> -
> -		if (encoder->pre_disable)
> -			encoder->pre_disable(state, encoder, old_crtc_state,
> -					     old_conn_state);
> -	}
> -}
> -
>  static void intel_encoders_disable(struct intel_atomic_state *state,
>  				   struct intel_crtc *crtc)
>  {
> @@ -9807,8 +9785,6 @@ static void intel_old_crtc_state_disables(struct intel_atomic_state *state,
>  
>  	drm_WARN_ON(&dev_priv->drm, old_crtc_state->bigjoiner_slave);
>  
> -	intel_encoders_pre_disable(state, crtc);
> -
>  	intel_crtc_disable_planes(state, crtc);
>  
>  	/*
> diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
> index e9e806d90eec..7d852affead1 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> @@ -196,10 +196,6 @@ struct intel_encoder {
>  	void (*update_complete)(struct intel_atomic_state *,
>  				struct intel_encoder *,
>  				struct intel_crtc *);
> -	void (*pre_disable)(struct intel_atomic_state *,
> -			    struct intel_encoder *,
> -			    const struct intel_crtc_state *,
> -			    const struct drm_connector_state *);
>  	void (*disable)(struct intel_atomic_state *,
>  			struct intel_encoder *,
>  			const struct intel_crtc_state *,
> diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> index d104441344c0..914bea983a28 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> @@ -348,16 +348,6 @@ static void wait_for_act_sent(struct intel_encoder *encoder,
>  	drm_dp_check_act_status(&intel_dp->mst_mgr);
>  }
>  
> -static void intel_mst_pre_disable_dp(struct intel_atomic_state *state,
> -				     struct intel_encoder *encoder,
> -				     const struct intel_crtc_state *old_crtc_state,
> -				     const struct drm_connector_state *old_conn_state)
> -{
> -	if (old_crtc_state->has_audio)
> -		intel_audio_codec_disable(encoder, old_crtc_state,
> -					  old_conn_state);
> -}
> -
>  static void intel_mst_disable_dp(struct intel_atomic_state *state,
>  				 struct intel_encoder *encoder,
>  				 const struct intel_crtc_state *old_crtc_state,
> @@ -382,6 +372,9 @@ static void intel_mst_disable_dp(struct intel_atomic_state *state,
>  	if (ret) {
>  		drm_dbg_kms(&i915->drm, "failed to update payload %d\n", ret);
>  	}
> +	if (old_crtc_state->has_audio)
> +		intel_audio_codec_disable(encoder,
> +					  old_crtc_state, old_conn_state);
>  }
>  
>  static void intel_mst_post_disable_dp(struct intel_atomic_state *state,
> @@ -905,7 +898,6 @@ intel_dp_create_fake_mst_encoder(struct intel_digital_port *dig_port, enum pipe
>  
>  	intel_encoder->compute_config = intel_dp_mst_compute_config;
>  	intel_encoder->compute_config_late = intel_dp_mst_compute_config_late;
> -	intel_encoder->pre_disable = intel_mst_pre_disable_dp;
>  	intel_encoder->disable = intel_mst_disable_dp;
>  	intel_encoder->post_disable = intel_mst_post_disable_dp;
>  	intel_encoder->update_pipe = intel_ddi_update_pipe;