Re: [PATCH] drm: rcar-du: Use drmm_encoder_alloc() to manage encoder

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Kieran,

Thank you for the patch.

On Wed, Jan 13, 2021 at 05:02:53PM +0000, Kieran Bingham wrote:
> The encoder allocation was converted to a DRM managed resource at the
> same time as the addition of a new helper drmm_encoder_alloc() which
> simplifies the same process.
> 
> Convert the custom drm managed resource allocation of the encoder
> with the helper to simplify the implementation, and prevent hitting a
> WARN_ON() due to the handling the drm_encoder_init() call directly
> without registering a .destroy() function op.
> 
> Fixes: f5f16725edbc ("drm: rcar-du: Use DRM-managed allocation for encoders")

We could equally point to the patch that has added drmm_encoder_alloc(),
but I'm fine taking the blame :-)

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

> Reported-by: Geert Uytterhoeven <geert+renesas@glider.be>
> Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
> ---
>  drivers/gpu/drm/rcar-du/rcar_du_encoder.c | 31 +++++------------------
>  1 file changed, 6 insertions(+), 25 deletions(-)
> 
> diff --git a/drivers/gpu/drm/rcar-du/rcar_du_encoder.c b/drivers/gpu/drm/rcar-du/rcar_du_encoder.c
> index ba8c6038cd63..ca3761772211 100644
> --- a/drivers/gpu/drm/rcar-du/rcar_du_encoder.c
> +++ b/drivers/gpu/drm/rcar-du/rcar_du_encoder.c
> @@ -48,21 +48,12 @@ static unsigned int rcar_du_encoder_count_ports(struct device_node *node)
>  static const struct drm_encoder_funcs rcar_du_encoder_funcs = {
>  };
>  
> -static void rcar_du_encoder_release(struct drm_device *dev, void *res)
> -{
> -	struct rcar_du_encoder *renc = res;
> -
> -	drm_encoder_cleanup(&renc->base);
> -	kfree(renc);
> -}
> -
>  int rcar_du_encoder_init(struct rcar_du_device *rcdu,
>  			 enum rcar_du_output output,
>  			 struct device_node *enc_node)
>  {
>  	struct rcar_du_encoder *renc;
>  	struct drm_bridge *bridge;
> -	int ret;
>  
>  	/*
>  	 * Locate the DRM bridge from the DT node. For the DPAD outputs, if the
> @@ -101,26 +92,16 @@ int rcar_du_encoder_init(struct rcar_du_device *rcdu,
>  			return -ENOLINK;
>  	}
>  
> -	renc = kzalloc(sizeof(*renc), GFP_KERNEL);
> -	if (renc == NULL)
> -		return -ENOMEM;
> -
> -	renc->output = output;
> -
>  	dev_dbg(rcdu->dev, "initializing encoder %pOF for output %u\n",
>  		enc_node, output);
>  
> -	ret = drm_encoder_init(&rcdu->ddev, &renc->base, &rcar_du_encoder_funcs,
> -			       DRM_MODE_ENCODER_NONE, NULL);
> -	if (ret < 0) {
> -		kfree(renc);
> -		return ret;
> -	}
> +	renc = drmm_encoder_alloc(&rcdu->ddev, struct rcar_du_encoder, base,
> +				  &rcar_du_encoder_funcs, DRM_MODE_ENCODER_NONE,
> +				  NULL);
> +	if (!renc)
> +		return -ENOMEM;
>  
> -	ret = drmm_add_action_or_reset(&rcdu->ddev, rcar_du_encoder_release,
> -				       renc);
> -	if (ret)
> -		return ret;
> +	renc->output = output;
>  
>  	/*
>  	 * Attach the bridge to the encoder. The bridge will create the

-- 
Regards,

Laurent Pinchart
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