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Fri, 31 Oct 2025 09:14:46 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=dkim; t=1761898491; h=from:subject:date:message-id:to:cc:mime-version:content-type: content-transfer-encoding:in-reply-to:references; bh=5kqeQwCaBXcdDdY/fhWUYtRy6WjKsRWcRbvT6plygZk=; b=T1ygqf85lOMPWNIDgy20hrud9rCyd1xYGw6YtoFTSBH3pQHtW1WHik1l52Ilu0OT6lsl/L zHbQrU6Klq8WUqyjfkbqD9cE5v1+IHAHs3ioVdpqt4SZ+4sVt52p45QAqmqiNS4tAT6jN4 JcFj+iG9CLwUNVoTsgr3/ZvFloNGRaGHDiWEJFsdStw7t0+V8b1u/1Cl4GZQUUToGmJ0Lj Aqk8f1rIgCxzN3KcXKmwhU9EE9CdtmRjNu8cIpT9LENVwKr1icISps9Ay8L6Yvp7cxG2ju K4FEKe9rAKcgYlnMBOvrU+XSh0Q0AWraH9ZR4sWbJefClS7Y3DjOAJX7nyVD2g== Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Fri, 31 Oct 2025 09:14:45 +0100 Message-Id: To: "Laurentiu Palcu" , , "Maarten Lankhorst" , "Maxime Ripard" , "Thomas Zimmermann" , "David Airlie" , "Simona Vetter" , "Shawn Guo" , "Sascha Hauer" , "Pengutronix Kernel Team" , "Fabio Estevam" Cc: , "Sandor Yu" , , Subject: Re: [PATCH v5 5/9] drm/imx: Add support for i.MX94 DCIF From: "Luca Ceresoli" X-Mailer: aerc 0.20.1 References: <20250911-dcif-upstreaming-v5-0-a1e8dab8ae40@oss.nxp.com> <20250911-dcif-upstreaming-v5-5-a1e8dab8ae40@oss.nxp.com> In-Reply-To: <20250911-dcif-upstreaming-v5-5-a1e8dab8ae40@oss.nxp.com> X-Last-TLS-Session-Version: TLSv1.3 Hello Laurentiu, On Thu Sep 11, 2025 at 1:37 PM CEST, Laurentiu Palcu wrote: ... > +static struct drm_bridge *dcif_crtc_get_bridge(struct drm_crtc *crtc, > + struct drm_crtc_state *crtc_state) > +{ > + struct drm_connector_state *conn_state; > + struct drm_encoder *encoder; > + struct drm_connector *conn; > + struct drm_bridge *bridge; > + int i; > + > + for_each_new_connector_in_state(crtc_state->state, conn, conn_state, i)= { > + if (crtc !=3D conn_state->crtc) > + continue; > + > + encoder =3D conn_state->best_encoder; > + > + bridge =3D drm_bridge_chain_get_first_bridge(encoder); The bridge returned by drm_bridge_chain_get_first_bridge() is refcounted since v6.18-rc1 [0], so you have to put that reference... > + if (bridge) > + return bridge; > + } > + > + return NULL; > +} > + > +static void dcif_crtc_query_output_bus_format(struct drm_crtc *crtc, > + struct drm_crtc_state *crtc_state) > +{ > + struct dcif_crtc_state *dcif_state =3D to_dcif_crtc_state(crtc_state); > + struct drm_bridge_state *bridge_state; > + struct drm_bridge *bridge; > + > + dcif_state->bus_format =3D MEDIA_BUS_FMT_RGB888_1X24; > + dcif_state->bus_flags =3D 0; > + > + bridge =3D dcif_crtc_get_bridge(crtc, crtc_state); > + if (!bridge) > + return; > + > + bridge_state =3D drm_atomic_get_new_bridge_state(crtc_state->state, bri= dge); > + if (!bridge_state) > + return; > + > + dcif_state->bus_format =3D bridge_state->input_bus_cfg.format; > + dcif_state->bus_flags =3D bridge_state->input_bus_cfg.flags; ...perhaps here, when both the bridge pointer and the bridge_state pointer referencing it go out of scope. > +} You can just call drm_bridge_put(bridge) there, or (at your option) use a cleanup action: static void dcif_crtc_query_output_bus_format(struct drm_crtc *crtc, struct drm_crtc_state *crtc_= state) { struct dcif_crtc_state *dcif_state =3D to_dcif_crtc_state(crtc_sta= te); struct drm_bridge_state *bridge_state; - struct drm_bridge *bridge; dcif_state->bus_format =3D MEDIA_BUS_FMT_RGB888_1X24; dcif_state->bus_flags =3D 0; - bridge =3D dcif_crtc_get_bridge(crtc, crtc_state); + struct drm_bridge *bridge __free(drm_bridge_put) =3D dcif_crtc_get= _bridge(crtc, crtc_state); if (!bridge) return; bridge_state =3D drm_atomic_get_new_bridge_state(crtc_state->state= , bridge); if (!bridge_state) return; dcif_state->bus_format =3D bridge_state->input_bus_cfg.format; dcif_state->bus_flags =3D bridge_state->input_bus_cfg.flags; } This would call drm_bridge_put() at end of scope, i.e. end of function. You can also have a look at recent commits involving drm_bridge_put (git log -p -Gdrm_bridge_put v6.16..origin/master) to see how other parts of the kernel have added drm_bridge_put(). [0] https://gitlab.freedesktop.org/drm/misc/kernel/-/commit/8fa5909400f3773= 51836419223c33f1131f0f7d3 Best regards, Luca --- Luca Ceresoli, Bootlin Embedded Linux and Kernel engineering https://bootlin.com