Re: [PATCH v2 3/7] drm/bridge: dw-mipi-dsi: stop using deprecated devm_drm_of_get_bridge()

[Paul Cercueil]

Hi Lucas,

Le mardi 29 septembre 2026 à 15:39 +0200, Luca Ceresoli a écrit :
> devm_drm_of_get_bridge() is deprecated, switch to
> of_drm_get_bridge_by_endpoint(). As of_drm_get_bridge_by_endpoint() returns
> a refcounted bridge, ensure it is put by using bridge.next_bridge.
> 
> Fixes build failure when CONFIG_OF is disabled.
> 
> Fixes: aa8a8c7e4641 ("drm/bridge: panel: move all code to drm_panel.c")
> Reported-by: Arnd Bergmann <arnd@xxxxxxxxxx>
> Closes: https://lore.kernel.org/r/20260928161605.2271412-1-arnd@xxxxxxxxxx
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> Closes:
> https://lore.kernel.org/oe-kbuild-all/202609291109.9RGna4XZ-lkp@xxxxxxxxx/
> Signed-off-by: Luca Ceresoli <luca.ceresoli@xxxxxxxxxxx>

Reviewed-by: Paul Cercueil <paul.cercueil@xxxxxxxxxxx>

With one nitpick below.

> 
> ---
> 
> Changes in v2:
> - fix bridge reference leak on attach error and detach paths
> - mention lkp report
> ---
>  drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 11 +++++------
>  1 file changed, 5 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> index 5dd475fcaacf..22d1b8cbe1d5 100644
> --- a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> +++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> @@ -244,7 +244,6 @@ struct debugfs_entries {
>  struct dw_mipi_dsi {
>  	struct drm_bridge bridge;
>  	struct mipi_dsi_host dsi_host;
> -	struct drm_bridge *panel_bridge;
>  	struct device *dev;
>  	void __iomem *base;
>  
> @@ -333,12 +332,12 @@ static int dw_mipi_dsi_host_attach(struct mipi_dsi_host
> *host,
>  	dsi->format = device->format;
>  	dsi->mode_flags = device->mode_flags;
>  
> -	bridge = devm_drm_of_get_bridge(dsi->dev, dsi->dev->of_node, 1, 0);
> +	bridge = of_drm_get_bridge_by_endpoint(dsi->dev->of_node, 1, 0);
>  	if (IS_ERR(bridge))
>  		return PTR_ERR(bridge);
>  
>  	bridge->pre_enable_prev_first = true;
> -	dsi->panel_bridge = bridge;
> +	dsi->bridge.next_bridge = bridge;
>  
>  	drm_bridge_add(&dsi->bridge);
>  
> @@ -352,6 +351,7 @@ static int dw_mipi_dsi_host_attach(struct mipi_dsi_host
> *host,
>  
>  err_remove_bridge:
>  	drm_bridge_remove(&dsi->bridge);
> +	drm_bridge_clear_and_put(&dsi->bridge.next_bridge);
>  	return ret;
>  }
>  
> @@ -368,9 +368,8 @@ static int dw_mipi_dsi_host_detach(struct mipi_dsi_host
> *host,
>  			return ret;
>  	}
>  
> -	drm_of_panel_bridge_remove(host->dev->of_node, 1, 0);
> -
>  	drm_bridge_remove(&dsi->bridge);
> +	drm_bridge_clear_and_put(&dsi->bridge.next_bridge);
>  
>  	return 0;
>  }
> @@ -1086,7 +1085,7 @@ static int dw_mipi_dsi_bridge_attach(struct drm_bridge
> *bridge,
>  	encoder->encoder_type = DRM_MODE_ENCODER_DSI;
>  
>  	/* Attach the panel-bridge to the dsi bridge */
> -	return drm_bridge_attach(encoder, dsi->panel_bridge, bridge,
> +	return drm_bridge_attach(encoder, dsi->bridge.next_bridge, bridge,
>  				 flags);

It would look a little bit better to have 'bridge' moved to the line below I
think. No big deal.

Cheers,
-Paul