[PATCH v5 11/13] drm/atomic-helper: Separate out Encoder-Bridge enable and disable

[Dmitry Baryshkov]

On Sun, Oct 20, 2024 at 01:35:28AM +0530, Aradhya Bhatia wrote:
> From: Aradhya Bhatia <a-bhatia1 at ti.com>
> 
> The way any singular display pipeline, in need of a modeset, gets
> enabled is as follows -
> 
> 	CRTC Enable
> 	All Bridge Pre-Enable
> 	Encoder Enable
> 	All Bridge Enable
> 
> - and the disable path is exactly the reverse of this.
> 
> The CRTC enable/disable occurs by looping over the old and new CRTC
> states, while the bridge pre-enable, encoder enable, and bridge enable
> occur by looping through the new connector states of the display
> pipelines.
> 
> At the moment, the encoder and bridge operations are grouped together
> and occur under the same loops.
> 
> Separate out the enable/disable loops of the encoder and bridge
> operations into a different function, to make way for the re-ordering of
> the enable and disable sequence of all these display elements.
> 
> This patch doesn't alter in any way the ordering of CRTC/encoder/bridge
> enable and disable, but merely helps to cleanly set up for the next
> patch and to make sure that the bisectibility remains intact.
> 
> Signed-off-by: Aradhya Bhatia <a-bhatia1 at ti.com>
> Signed-off-by: Aradhya Bhatia <aradhya.bhatia at linux.dev>
> ---
>  drivers/gpu/drm/drm_atomic_helper.c | 97 +++++++++++++++++------------
>  1 file changed, 57 insertions(+), 40 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
> index 5186d2114a50..7741fbcc8fc7 100644
> --- a/drivers/gpu/drm/drm_atomic_helper.c
> +++ b/drivers/gpu/drm/drm_atomic_helper.c
> @@ -1122,11 +1122,10 @@ crtc_needs_disable(struct drm_crtc_state *old_state,
>  }
>  
>  static void
> -disable_outputs(struct drm_device *dev, struct drm_atomic_state *old_state)
> +encoder_bridge_chain_disable(struct drm_device *dev, struct drm_atomic_state *old_state)
>  {
>  	struct drm_connector *connector;
>  	struct drm_connector_state *old_conn_state, *new_conn_state;
> -	struct drm_crtc *crtc;
>  	struct drm_crtc_state *old_crtc_state, *new_crtc_state;
>  	int i;
>  
> @@ -1189,6 +1188,16 @@ disable_outputs(struct drm_device *dev, struct drm_atomic_state *old_state)
>  
>  		drm_atomic_bridge_chain_post_disable(bridge, old_state);
>  	}
> +}
> +
> +static void
> +disable_outputs(struct drm_device *dev, struct drm_atomic_state *old_state)
> +{
> +	struct drm_crtc *crtc;
> +	struct drm_crtc_state *old_crtc_state, *new_crtc_state;
> +	int i;
> +
> +	encoder_bridge_chain_disable(dev, old_state);
>  
>  	for_each_oldnew_crtc_in_state(old_state, crtc, old_crtc_state, new_crtc_state, i) {
>  		const struct drm_crtc_helper_funcs *funcs;
> @@ -1445,6 +1454,51 @@ static void drm_atomic_helper_commit_writebacks(struct drm_device *dev,
>  	}
>  }
>  
> +static void
> +encoder_bridge_chain_enable(struct drm_device *dev, struct drm_atomic_state *old_state)
> +{
> +	struct drm_connector *connector;
> +	struct drm_connector_state *new_conn_state;
> +	int i;
> +
> +	for_each_new_connector_in_state(old_state, connector, new_conn_state, i) {
> +		const struct drm_encoder_helper_funcs *funcs;
> +		struct drm_encoder *encoder;
> +		struct drm_bridge *bridge;
> +
> +		if (!new_conn_state->best_encoder)
> +			continue;
> +
> +		if (!new_conn_state->crtc->state->active ||
> +		    !drm_atomic_crtc_needs_modeset(new_conn_state->crtc->state))
> +			continue;
> +
> +		encoder = new_conn_state->best_encoder;
> +		funcs = encoder->helper_private;
> +
> +		drm_dbg_atomic(dev, "enabling [ENCODER:%d:%s]\n",
> +			       encoder->base.id, encoder->name);
> +
> +		/*
> +		 * Each encoder has at most one connector (since we always steal
> +		 * it away), so we won't call enable hooks twice.
> +		 */
> +		bridge = drm_bridge_chain_get_first_bridge(encoder);
> +		drm_atomic_bridge_chain_pre_enable(bridge, old_state);
> +
> +		if (funcs) {
> +			if (funcs->atomic_enable)
> +				funcs->atomic_enable(encoder, old_state);
> +			else if (funcs->enable)
> +				funcs->enable(encoder);
> +			else if (funcs->commit)
> +				funcs->commit(encoder);
> +		}
> +
> +		drm_atomic_bridge_chain_enable(bridge, old_state);
> +	}
> +}
> +
>  /**
>   * drm_atomic_helper_commit_modeset_enables - modeset commit to enable outputs
>   * @dev: DRM device
> @@ -1465,8 +1519,6 @@ void drm_atomic_helper_commit_modeset_enables(struct drm_device *dev,
>  	struct drm_crtc *crtc;
>  	struct drm_crtc_state *old_crtc_state;
>  	struct drm_crtc_state *new_crtc_state;
> -	struct drm_connector *connector;
> -	struct drm_connector_state *new_conn_state;
>  	int i;
>  
>  	for_each_oldnew_crtc_in_state(old_state, crtc, old_crtc_state, new_crtc_state, i) {
> @@ -1491,42 +1543,7 @@ void drm_atomic_helper_commit_modeset_enables(struct drm_device *dev,
>  		}
>  	}

I'd say, if you want for it to be cleaner, split both loops from
drm_atomic_helper_commit_modeset_enables() and call them separately.
This save you from the code move, which is harder to review (and also
helps with the function complexity).

>  
> -	for_each_new_connector_in_state(old_state, connector, new_conn_state, i) {
> -		const struct drm_encoder_helper_funcs *funcs;
> -		struct drm_encoder *encoder;
> -		struct drm_bridge *bridge;
> -
> -		if (!new_conn_state->best_encoder)
> -			continue;
> -
> -		if (!new_conn_state->crtc->state->active ||
> -		    !drm_atomic_crtc_needs_modeset(new_conn_state->crtc->state))
> -			continue;
> -
> -		encoder = new_conn_state->best_encoder;
> -		funcs = encoder->helper_private;
> -
> -		drm_dbg_atomic(dev, "enabling [ENCODER:%d:%s]\n",
> -			       encoder->base.id, encoder->name);
> -
> -		/*
> -		 * Each encoder has at most one connector (since we always steal
> -		 * it away), so we won't call enable hooks twice.
> -		 */
> -		bridge = drm_bridge_chain_get_first_bridge(encoder);
> -		drm_atomic_bridge_chain_pre_enable(bridge, old_state);
> -
> -		if (funcs) {
> -			if (funcs->atomic_enable)
> -				funcs->atomic_enable(encoder, old_state);
> -			else if (funcs->enable)
> -				funcs->enable(encoder);
> -			else if (funcs->commit)
> -				funcs->commit(encoder);
> -		}
> -
> -		drm_atomic_bridge_chain_enable(bridge, old_state);
> -	}
> +	encoder_bridge_chain_enable(dev, old_state);
>  
>  	drm_atomic_helper_commit_writebacks(dev, old_state);
>  }
> -- 
> 2.34.1
> 

-- 
With best wishes
Dmitry