From nobody Fri Oct 24 13:53:20 2025 Received: from smtpout-02.galae.net (smtpout-02.galae.net [185.246.84.56]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 371902874F8 for ; Tue, 21 Oct 2025 21:01:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.246.84.56 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761080491; cv=none; b=bLCD+BA2aKYoJKaIFcf9xz+4SzlWtzB7PNgs9fdJCIyUIgBqhGdG3QUIDprLTPUXJ8WKxhN7srk/QPGWwftgM+w9dqAbM6b2f0+SgRvTLzn7AYiYxs/Yo0aIAIvQa0tJq44oSTugm5BZx/4yNiaU297QXYVKcFauQ+qyqJcy/NM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761080491; c=relaxed/simple; bh=pBjfUdjbqY9Yz36hon7vReamWFx77NrxoFtcL3aa/+w=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=bqgWK34BjvVUw5ZMMCGPRnKGFes+YPh9yGMMpPsjQkCK9DEV6Qo3JdjAGXGAKhNb5LAjpjxJ/0D6nrvobW/M4RB/RpBe7lNIigzQaE/qT5ODUyf//VumzgmP4a2TKgRs5icUBfWlrpqQucWx0T7XO3Nysu9aiAW/94UEhYR7gGY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com; spf=pass smtp.mailfrom=bootlin.com; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b=UDm4nEbE; arc=none smtp.client-ip=185.246.84.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bootlin.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b="UDm4nEbE" Received: from smtpout-01.galae.net (smtpout-01.galae.net [212.83.139.233]) by smtpout-02.galae.net (Postfix) with ESMTPS id 96A001A15AC; Tue, 21 Oct 2025 21:01:28 +0000 (UTC) Received: from mail.galae.net (mail.galae.net [212.83.136.155]) by smtpout-01.galae.net (Postfix) with ESMTPS id 6D90C60680; Tue, 21 Oct 2025 21:01:28 +0000 (UTC) Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id 49BDC102F241F; Tue, 21 Oct 2025 23:01:24 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=dkim; t=1761080487; h=from:subject:date:message-id:to:cc:mime-version:content-type: content-transfer-encoding:in-reply-to:references; bh=p/3IIpo2fKAEaKJeCKwn/2EO3bVCvyymxE4cdcCqCkM=; b=UDm4nEbE2HVXl+I3B42iVs765XRRw5DrLs4OqZ8TN28Zgn1tG1P9TwxzSlsd/FV5QPNwJB 1yiF7otbpl/9zsaTwRRYASbxZ3rhJYmjhCyfVnej+Y7r6JdEm1aYv+Ud4cjhHAj6DQWKXU C0LyDAbZeUmsaJy8jXiPo9pkUUj5fpK4byb4o/v7N0jm9lK2YaM6vGbwKqnTI9oIUSR/6K K1VYcxKgw4VeWiRPwqidIoVDBqdW5ej4l1PwsaImB8PZjvzac9I3suR1kz3RWZguHYfoSx o5xw9jKjUH6sejwG+HBIHl1pMkTFZ95YFyrLsCZffqMuwBUgvPS2CUT6t/AmiQ== From: Luca Ceresoli Date: Tue, 21 Oct 2025 23:00:47 +0200 Subject: [PATCH v2 4/5] drm/bridge: add warning for bridges attached without being added Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20251021-b4-drm-bridge-alloc-add-before-attach-v2-4-c17cc1bbff72@bootlin.com> References: <20251021-b4-drm-bridge-alloc-add-before-attach-v2-0-c17cc1bbff72@bootlin.com> In-Reply-To: <20251021-b4-drm-bridge-alloc-add-before-attach-v2-0-c17cc1bbff72@bootlin.com> To: Alain Volmat , Raphael Gallais-Pou , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Andrzej Hajda , Neil Armstrong , Robert Foss , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Raphael Gallais-Pou Cc: Hui Pu , Thomas Petazzoni , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Luca Ceresoli X-Mailer: b4 0.14.2 X-Last-TLS-Session-Version: TLSv1.3 DRM bridges must be added before they are attached. Add a warning to catch violations. The warning is based on the bridge not being part of any list, so it will trigger if the bridge is being attached without ever having been added. It won't catch cases of bridges attached after having been added and then removed, because in that case the bridge will be in bridge_lingering_list. However such a case is both more demanding to detect and less likely to happen, so it can be left unchecked, at least for now. Link: https://lore.kernel.org/all/20250709-sophisticated-loon-of-rain-6ccdd= 8@houat/ Reviewed-by: Raphael Gallais-Pou Signed-off-by: Luca Ceresoli --- drivers/gpu/drm/drm_bridge.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c index 1246a52f8767b52c5f10139aa897824b3c2f28da..6dba601a056bb3cff8b8dd5b1ec= 46299235b2d85 100644 --- a/drivers/gpu/drm/drm_bridge.c +++ b/drivers/gpu/drm/drm_bridge.c @@ -441,6 +441,9 @@ int drm_bridge_attach(struct drm_encoder *encoder, stru= ct drm_bridge *bridge, if (!encoder || !bridge) return -EINVAL; =20 + if (list_empty(&bridge->list)) + DRM_WARN("Missing drm_bridge_add() before attach\n"); + drm_bridge_get(bridge); =20 if (previous && (!previous->dev || previous->encoder !=3D encoder)) { --=20 2.51.0