Re: [PATCH 02/26] drm/bridge: deprecate of_drm_find_bridge()

From: "Luca Ceresoli" <luca.ceresoli@bootlin.com>
To: "Louis Chauvet" <louis.chauvet@bootlin.com>,
	"Andrzej Hajda" <andrzej.hajda@intel.com>,
	"Neil Armstrong" <neil.armstrong@linaro.org>,
	"Robert Foss" <rfoss@kernel.org>,
	"Laurent Pinchart" <Laurent.pinchart@ideasonboard.com>,
	"Jonas Karlman" <jonas@kwiboo.se>,
	"Jernej Skrabec" <jernej.skrabec@gmail.com>,
	"Maarten Lankhorst" <maarten.lankhorst@linux.intel.com>,
	"Maxime Ripard" <mripard@kernel.org>,
	"Thomas Zimmermann" <tzimmermann@suse.de>,
	"David Airlie" <airlied@gmail.com>,
	"Simona Vetter" <simona@ffwll.ch>,
	"Jonathan Corbet" <corbet@lwn.net>,
	"Alexey Brodkin" <abrodkin@synopsys.com>,
	"Phong LE" <ple@baylibre.com>, "Liu Ying" <victor.liu@nxp.com>,
	"Shawn Guo" <shawnguo@kernel.org>,
	"Sascha Hauer" <s.hauer@pengutronix.de>,
	"Pengutronix Kernel Team" <kernel@pengutronix.de>,
	"Fabio Estevam" <festevam@gmail.com>,
	"Adrien Grassein" <adrien.grassein@gmail.com>,
	"Laurent Pinchart" <laurent.pinchart+renesas@ideasonboard.com>,
	"Tomi Valkeinen" <tomi.valkeinen+renesas@ideasonboard.com>,
	"Kieran Bingham" <kieran.bingham+renesas@ideasonboard.com>,
	"Geert Uytterhoeven" <geert+renesas@glider.be>,
	"Magnus Damm" <magnus.damm@gmail.com>,
	"Kevin Hilman" <khilman@baylibre.com>,
	"Jerome Brunet" <jbrunet@baylibre.com>,
	"Martin Blumenstingl" <martin.blumenstingl@googlemail.com>,
	"Chun-Kuang Hu" <chunkuang.hu@kernel.org>,
	"Philipp Zabel" <p.zabel@pengutronix.de>,
	"Matthias Brugger" <matthias.bgg@gmail.com>,
	"AngeloGioacchino Del Regno"
	<angelogioacchino.delregno@collabora.com>,
	"Anitha Chrisanthus" <anitha.chrisanthus@intel.com>,
	"Edmund Dea" <edmund.j.dea@intel.com>,
	"Inki Dae" <inki.dae@samsung.com>,
	"Seung-Woo Kim" <sw0312.kim@samsung.com>,
	"Kyungmin Park" <kyungmin.park@samsung.com>,
	"Krzysztof Kozlowski" <krzk@kernel.org>,
	"Alim Akhtar" <alim.akhtar@samsung.com>
Cc: "Hui Pu" <Hui.Pu@gehealthcare.com>,
	"Thomas Petazzoni" <thomas.petazzoni@bootlin.com>,
	<dri-devel@lists.freedesktop.org>, <linux-kernel@vger.kernel.org>,
	<linux-doc@vger.kernel.org>, <imx@lists.linux.dev>,
	<linux-arm-kernel@lists.infradead.org>,
	<linux-renesas-soc@vger.kernel.org>,
	<linux-amlogic@lists.infradead.org>,
	<linux-mediatek@lists.infradead.org>,
	<linux-samsung-soc@vger.kernel.org>
Subject: Re: [PATCH 02/26] drm/bridge: deprecate of_drm_find_bridge()
Date: Wed, 19 Nov 2025 16:13:41 +0100	[thread overview]
Message-ID: <DECRP2E0HI3I.APSIIQR4TVWK@bootlin.com> (raw)
In-Reply-To: <66cdbe39-d065-4aa4-86e4-84a38b49c09c@bootlin.com>

On Wed Nov 19, 2025 at 3:28 PM CET, Louis Chauvet wrote:
>
>
> On 11/19/25 13:05, Luca Ceresoli wrote:
>> of_drm_find_bridge() does not increment the returned bridge
>> refcount. drm_of_find_bridge() is to be used as a replacement.
>>
>> Suggested-by: Maxime Ripard <mripard@kernel.org>
>> Link: https://lore.kernel.org/dri-devel/20250319-stylish-lime-mongoose-0a18ad@houat/
>> Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>

...

>> @@ -1452,6 +1452,9 @@ EXPORT_SYMBOL(drm_of_find_bridge);
>>    *
>>    * @np: device node
>>    *
>> + * This function is deprecated. Use drm_of_find_bridge() instead for proper
>> + * refcounting.
>> + *
>
> I think it should be more explicit that the refcounting is not done by
> this function, like:
>
> 	This function is deprecated. The returned bridge is not refcounted, you
> should not use drm_bridge_put(). Use drm_of_find_bridge() instead for
> proper refcounting.

OK.

--
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com