linux-kernel - Re: [PATCH] drm/bridge: panel: Remove a redundant check on existence of bridge->encoder

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Date: Mon, 13 May 2024 00:14:25 +0300
From: Laurent Pinchart <laurent.pinchart@...asonboard.com>
To: Sui Jingfeng <sui.jingfeng@...ux.dev>
Cc: 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: panel: Remove a redundant check on existence
 of bridge->encoder

Hi Sui,

Thank you for the patch.

On Sat, May 11, 2024 at 10:03:16PM +0800, Sui Jingfeng wrote:
> In panel_bridge_attach(), the check on the existence of bridge->encoder
> has already been done in the implementation of drm_bridge_attach(). And
> it is done before the bridge->funcs->attach hook is called. Hence, it is
> guaranteed that the .encoder member of the struct drm_bridge is not NULL
> when the panel_bridge_attach() is called.
> 
> There is no need to check the existence of bridge->encoder another time
> at the implementation layer, therefore 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/panel.c | 5 -----
>  1 file changed, 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/panel.c b/drivers/gpu/drm/bridge/panel.c
> index 7f41525f7a6e..762402dca6dd 100644
> --- a/drivers/gpu/drm/bridge/panel.c
> +++ b/drivers/gpu/drm/bridge/panel.c
> @@ -65,11 +65,6 @@ static int panel_bridge_attach(struct drm_bridge *bridge,
>  	if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR)
>  		return 0;
>  
> -	if (!bridge->encoder) {
> -		DRM_ERROR("Missing encoder\n");
> -		return -ENODEV;
> -	}
> -
>  	drm_connector_helper_add(connector,
>  				 &panel_bridge_connector_helper_funcs);
>  

-- 
Regards,

Laurent Pinchart