linux-kernel - Re: [PATCH] drm/bridge: analogix: Remove redundant checks on existence of bridge->encoder

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Date: Mon, 13 May 2024 00:15:58 +0300
From: Laurent Pinchart <laurent.pinchart@...asonboard.com>
To: Sui Jingfeng <sui.jingfeng@...ux.dev>
Cc: Kieran Bingham <kieran.bingham@...asonboard.com>,
	Biju Das <biju.das.jz@...renesas.com>,
	Alicja Michalska <ahplka19@...il.com>,
	Chen-Yu Tsai <wenst@...omium.org>,
	Hsin-Yi Wang <hsinyi@...omium.org>,
	Maxime Ripard <mripard@...nel.org>,
	Andrzej Hajda <andrzej.hajda@...el.com>,
	Neil Armstrong <neil.armstrong@...aro.org>,
	Robert Foss <rfoss@...nel.org>, Jonas Karlman <jonas@...boo.se>,
	Jernej Skrabec <jernej.skrabec@...il.com>,
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
	Thomas Zimmermann <tzimmermann@...e.de>,
	dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] drm/bridge: analogix: Remove redundant checks on
 existence of bridge->encoder

Hi Sui,

Thank you for the patch.

On Sat, May 11, 2024 at 11:22:22PM +0800, Sui Jingfeng wrote:
> The check on the existence of bridge->encoder on the implementation layer
> of drm bridge driver is not necessary, as it has already been done in the
> drm_bridge_attach() function. It is guaranteed that the .encoder member
> of the drm_bridge instance is not NULL when various anxxxx_bridge_attach()
> function gets called. And .atomic_enable() of struct drm_bridge_funcs
> shouldn't be able to called before the various is acctached.
> 
> Remove the redundant checking codes "if (!bridge->encoder) { ... }".
> 
> Signed-off-by: Sui Jingfeng <sui.jingfeng@...ux.dev>

Reviewed-by: Laurent Pinchart <laurent.pinchart@...asonboard.com>

> ---
>  drivers/gpu/drm/bridge/analogix/analogix-anx6345.c |  5 -----
>  drivers/gpu/drm/bridge/analogix/analogix-anx78xx.c |  5 -----
>  drivers/gpu/drm/bridge/analogix/analogix_dp_core.c |  5 -----
>  drivers/gpu/drm/bridge/analogix/anx7625.c          | 10 ----------
>  4 files changed, 25 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix-anx6345.c b/drivers/gpu/drm/bridge/analogix/analogix-anx6345.c
> index c9e35731e6a1..cfe43d2ca3be 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix-anx6345.c
> +++ b/drivers/gpu/drm/bridge/analogix/analogix-anx6345.c
> @@ -528,11 +528,6 @@ static int anx6345_bridge_attach(struct drm_bridge *bridge,
>  		return -EINVAL;
>  	}
>  
> -	if (!bridge->encoder) {
> -		DRM_ERROR("Parent encoder object not found");
> -		return -ENODEV;
> -	}
> -
>  	/* Register aux channel */
>  	anx6345->aux.name = "DP-AUX";
>  	anx6345->aux.dev = &anx6345->client->dev;
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix-anx78xx.c b/drivers/gpu/drm/bridge/analogix/analogix-anx78xx.c
> index 5748a8581af4..58875dde496f 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix-anx78xx.c
> +++ b/drivers/gpu/drm/bridge/analogix/analogix-anx78xx.c
> @@ -897,11 +897,6 @@ static int anx78xx_bridge_attach(struct drm_bridge *bridge,
>  		return -EINVAL;
>  	}
>  
> -	if (!bridge->encoder) {
> -		DRM_ERROR("Parent encoder object not found");
> -		return -ENODEV;
> -	}
> -
>  	/* Register aux channel */
>  	anx78xx->aux.name = "DP-AUX";
>  	anx78xx->aux.dev = &anx78xx->client->dev;
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> index df9370e0ff23..7b841232321f 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> @@ -1228,11 +1228,6 @@ static int analogix_dp_bridge_attach(struct drm_bridge *bridge,
>  		return -EINVAL;
>  	}
>  
> -	if (!bridge->encoder) {
> -		DRM_ERROR("Parent encoder object not found");
> -		return -ENODEV;
> -	}
> -
>  	if (!dp->plat_data->skip_connector) {
>  		connector = &dp->connector;
>  		connector->polled = DRM_CONNECTOR_POLL_HPD;
> diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c b/drivers/gpu/drm/bridge/analogix/anx7625.c
> index 59e9ad349969..3d09efa4199c 100644
> --- a/drivers/gpu/drm/bridge/analogix/anx7625.c
> +++ b/drivers/gpu/drm/bridge/analogix/anx7625.c
> @@ -2193,11 +2193,6 @@ static int anx7625_bridge_attach(struct drm_bridge *bridge,
>  	if (!(flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR))
>  		return -EINVAL;
>  
> -	if (!bridge->encoder) {
> -		DRM_DEV_ERROR(dev, "Parent encoder object not found");
> -		return -ENODEV;
> -	}
> -
>  	ctx->aux.drm_dev = bridge->dev;
>  	err = drm_dp_aux_register(&ctx->aux);
>  	if (err) {
> @@ -2435,11 +2430,6 @@ static void anx7625_bridge_atomic_enable(struct drm_bridge *bridge,
>  
>  	dev_dbg(dev, "drm atomic enable\n");
>  
> -	if (!bridge->encoder) {
> -		dev_err(dev, "Parent encoder object not found");
> -		return;
> -	}
> -
>  	connector = drm_atomic_get_new_connector_for_encoder(state->base.state,
>  							     bridge->encoder);
>  	if (!connector)

-- 
Regards,

Laurent Pinchart