From nobody Tue Jun 23 07:07:43 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 41C8FC433F5 for ; Wed, 9 Mar 2022 14:32:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233548AbiCIOdN (ORCPT ); Wed, 9 Mar 2022 09:33:13 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59954 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229703AbiCIOdL (ORCPT ); Wed, 9 Mar 2022 09:33:11 -0500 Received: from relay9-d.mail.gandi.net (relay9-d.mail.gandi.net [IPv6:2001:4b98:dc4:8::229]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 77BE81520FE for ; Wed, 9 Mar 2022 06:32:11 -0800 (PST) Received: (Authenticated sender: paul.kocialkowski@bootlin.com) by mail.gandi.net (Postfix) with ESMTPSA id F3C35FF810; Wed, 9 Mar 2022 14:32:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1646836330; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=4yNE8unHQFaK7qSnkWkqczTG141cySTJ7pfi48d6wGI=; b=JSLpwvLwjh4zr2SARMq3/4EKIuKAzfnLT6dtVBbpVJSI9lfj+AdtHbu3lQ0KqXdK1Zdm7r p3uRrHJFghTZBLI/FfjKZ8hO3w2S0jk1ihjRUlmgNn9hk7bg0gHvreyBuAkaVfHfF9b/qm rP8UJm+DJpbSKqfyQqmgyyl4ocFMel5r+g3QXrsm7SyIknIa2SsJd0S/pGcVp+oMH+/j2g Ke/ycL7pqtg2h+6Ka51h1fmJySwkg6Evvn6qBnsdwIEgRn2iE2HZceYW3mv0MKwXIMD8nb fpQIKa5Ttw95A+dtOJR6mPicRQheMthKZsGHEKuwSg0JxDDuXNyVnEKgZveTkQ== From: Paul Kocialkowski To: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Cc: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Daniel Vetter , Linus Walleij , Jagan Teki , Paul Kocialkowski Subject: [PATCH] drm: of: Properly try all possible cases for bridge/panel detection Date: Wed, 9 Mar 2022 15:32:00 +0100 Message-Id: <20220309143200.111292-1-paul.kocialkowski@bootlin.com> X-Mailer: git-send-email 2.35.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" While bridge/panel detection was initially relying on the usual port/ports-based of graph detection, it was recently changed to perform the lookup on any child node that is not port/ports instead when such a node is available, with no fallback on the usual way. This results in breaking detection when a child node is present but does not contain any panel or bridge node, even when the usual port/ports-based of graph is there. In order to support both situations properly, this commit reworks the logic to try both options and not just one of the two: it will only return -EPROBE_DEFER when both have failed. Signed-off-by: Paul Kocialkowski Fixes: 80253168dbfd ("drm: of: Lookup if child node has panel or bridge") --- drivers/gpu/drm/drm_of.c | 93 +++++++++++++++++++++------------------- 1 file changed, 49 insertions(+), 44 deletions(-) diff --git a/drivers/gpu/drm/drm_of.c b/drivers/gpu/drm/drm_of.c index 9d90cd75c457..67f1b7dfc892 100644 --- a/drivers/gpu/drm/drm_of.c +++ b/drivers/gpu/drm/drm_of.c @@ -219,6 +219,35 @@ int drm_of_encoder_active_endpoint(struct device_node = *node, } EXPORT_SYMBOL_GPL(drm_of_encoder_active_endpoint); =20 +static int drm_of_find_remote_panel_or_bridge(struct device_node *remote, + struct drm_panel **panel, + struct drm_bridge **bridge) +{ + int ret =3D -EPROBE_DEFER; + + if (panel) { + *panel =3D of_drm_find_panel(remote); + if (!IS_ERR(*panel)) + ret =3D 0; + else + *panel =3D NULL; + } + + /* No panel found yet, check for a bridge next. */ + if (bridge) { + if (ret) { + *bridge =3D of_drm_find_bridge(remote); + if (*bridge) + ret =3D 0; + } else { + *bridge =3D NULL; + } + + } + + return ret; +} + /** * drm_of_find_panel_or_bridge - return connected panel or bridge device * @np: device tree node containing encoder output ports @@ -249,57 +278,33 @@ int drm_of_find_panel_or_bridge(const struct device_n= ode *np, if (panel) *panel =3D NULL; =20 - /** - * Devices can also be child nodes when we also control that device - * through the upstream device (ie, MIPI-DCS for a MIPI-DSI device). - * - * Lookup for a child node of the given parent that isn't either port - * or ports. - */ - for_each_available_child_of_node(np, remote) { - if (of_node_name_eq(remote, "port") || - of_node_name_eq(remote, "ports")) - continue; - - goto of_find_panel_or_bridge; + /* Check for a graph on the device node first. */ + if (of_graph_is_present(np)) { + remote =3D of_graph_get_remote_node(np, port, endpoint); + if (remote) { + ret =3D drm_of_find_remote_panel_or_bridge(remote, panel, + bridge); + of_node_put(remote); + } } =20 - /* - * of_graph_get_remote_node() produces a noisy error message if port - * node isn't found and the absence of the port is a legit case here, - * so at first we silently check whether graph presents in the - * device-tree node. - */ - if (!of_graph_is_present(np)) - return -ENODEV; - - remote =3D of_graph_get_remote_node(np, port, endpoint); - -of_find_panel_or_bridge: - if (!remote) - return -ENODEV; + /* Otherwise check for any child node other than port/ports. */ + if (ret) { + for_each_available_child_of_node(np, remote) { + if (of_node_name_eq(remote, "port") || + of_node_name_eq(remote, "ports")) + continue; =20 - if (panel) { - *panel =3D of_drm_find_panel(remote); - if (!IS_ERR(*panel)) - ret =3D 0; - else - *panel =3D NULL; - } + ret =3D drm_of_find_remote_panel_or_bridge(remote, panel, + bridge); + of_node_put(remote); =20 - /* No panel found yet, check for a bridge next. */ - if (bridge) { - if (ret) { - *bridge =3D of_drm_find_bridge(remote); - if (*bridge) - ret =3D 0; - } else { - *bridge =3D NULL; + /* Stop at the first found occurrence. */ + if (!ret) + break; } - } =20 - of_node_put(remote); return ret; } EXPORT_SYMBOL_GPL(drm_of_find_panel_or_bridge); --=20 2.35.1