From mboxrd@z Thu Jan 1 00:00:00 1970 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 D143D2EDD62 for ; Tue, 28 Apr 2026 15:31:23 +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=1777390286; cv=none; b=femhgZ6iZSUMMp+8xsvxzO1BRNpgEER3HnPKTGNxW+mkIyjDZOx1aUQQrPxsi8EFr4vItFs9ypqpGkwVIocajPJgmd79xLk1yNOOH0RXcYUzrFFcAl822nG4gMA8huo8fMdxWQcy6ZxjoZuJPbnn7I+viV3jkqqSiFfsDHTDY04= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777390286; c=relaxed/simple; bh=yL/BsvDRd38fz43ec/fuPnaAzJeSeSU0uTrb9reLZ0Y=; h=From:Subject:Date:Message-Id:MIME-Version:Content-Type:To:Cc; b=cy8SkiXnbnEuNh2W3n4dY2Io0jXKo0QlJNGnjcCA9VKFhpV5adtwN7IOZNVS8oIneXdm+Pakf4Fb1hhE9IJ96Wy0+tVV2M6Ip49QDKWBllCkT7QYsTVzQAJBzdd1/ZN8PyVw2/TCw7kgdCdUjWUvcaaxGskVOCDGs+lgfnfyw+w= 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=AOKI61nm; 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="AOKI61nm" Received: from smtpout-01.galae.net (smtpout-01.galae.net [212.83.139.233]) by smtpout-02.galae.net (Postfix) with ESMTPS id 2956D1A3472; Tue, 28 Apr 2026 15:31:22 +0000 (UTC) Received: from mail.galae.net (mail.galae.net [212.83.136.155]) by smtpout-01.galae.net (Postfix) with ESMTPS id E8B40601D0; Tue, 28 Apr 2026 15:31:21 +0000 (UTC) Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id 6752F1072861C; Tue, 28 Apr 2026 17:31:12 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=dkim; t=1777390280; h=from:subject:date:message-id:to:cc:mime-version:content-type: content-transfer-encoding; bh=OEF9VP5XUoD9pYJWbQoWCnjrQfSnlUkjr7ryReb47jg=; b=AOKI61nma48mkjqVr9Gb0ISnASEq8351KRUjUxWqAmufoigi8v8gQNPeUG8f6NrpREttuy FDlGkif5jmdraMwjeo5PB+wBrSrAsmy8r4Fc9tWTM/AiNLU6EpcWu7WyryalA9oIWDWt5j QqQwYL9Vd0e63jTQDaButn0NS4xNLxk4OAfhfrewW7IeETq9w78lYqk06W2flRsFU7Lfn3 gGTpOiupKUomuK8ijPXEo+RXSSJkdrTK8EF7Onj0e9xr9PohJjrsv8fLuuaeeAVzVDr7p5 pVIgV1WqujC0gJ9/mpnZ6BAXCGwFdRyXvciqoaJN+ajkcii4HobOrQqxrwdzjQ== From: Luca Ceresoli Subject: [PATCH v3 00/11] drm/bridge: handle refcounting for bridge-only callers of drm_of_find_panel_or_bridge() Date: Tue, 28 Apr 2026 17:30:49 +0200 Message-Id: <20260428-drm-bridge-alloc-getput-panel_or_bridge-v3-0-a537b5567add@bootlin.com> 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: 8bit X-B4-Tracking: v=1; b=H4sIAKnS8GkC/42O0Q6CIBiFX8VxHQ2Q0rrqPVpzCL9KU3CAruZ89 9Bqqzsvz87Z950JeXAaPDonE3Iwaq+tiSHdJUg2wtSAtYoZMcKOhFOCletw6bSKjWhbK3ENoR8 C7oWBtrCu+JScHQgt0xyEUCjSegeVfqym6+2d/VDeQYYFvywa7YN1z/XKSJfd15puto4UEyykI lSq7CRodSmtDa02e2k7tHhH9kNm+XYyi2SeEpJxLqjk2T95nucX8lgv3EwBAAA= X-Change-ID: 20260410-drm-bridge-alloc-getput-panel_or_bridge-42501b38eaad To: Andrzej Hajda , Neil Armstrong , Robert Foss , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Rob Clark , Dmitry Baryshkov , Abhinav Kumar , Jessica Zhang , Sean Paul , Marijn Suijten , Xinliang Liu , Sumit Semwal , Yongqin Liu , John Stultz , Tomi Valkeinen , Michal Simek Cc: Hui Pu , Ian Ray , Thomas Petazzoni , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, freedreno@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org, Luca Ceresoli , Laurent Pinchart , Dmitry Baryshkov X-Mailer: b4 0.15.2 X-Last-TLS-Session-Version: TLSv1.3 This series converts all the bridge-only callers of the deprecated drm_of_find_panel_or_bridge() API to a new, simpler API that handles bridge refcounting. == Series description * Patch 1 (new in v2) makes drm_bridge_get/put() ignore ERR_PTR pointers, not only NULL pointers * Patch 2 introduces of_drm_get_bridge_by_endpoint() as a replacement for bridge-only calls to drm_of_find_panel_or_bridge(); the new function refcounts the bridge and is simpler * The following patches convert all bridge-only users to the new API * The last patch forbids new bridge-only calls to drm_of_find_panel_or_bridge() == Grand plan This is part of the work to support hotplug of DRM bridges. The grand plan was discussed in [0]. Here's the work breakdown (➜ marks the current series): 1. ➜ add refcounting to DRM bridges struct drm_bridge, based on devm_drm_bridge_alloc() A. ✔ add new alloc API and refcounting (v6.16) B. ✔ convert all bridge drivers to new API (v6.17) C. ✔ kunit tests (v6.17) D. ✔ add get/put to drm_bridge_add/remove() + attach/detach() and warn on old allocation pattern (v6.17) E. ➜ add get/put on drm_bridge accessors 1. ✔ drm_bridge_chain_get_first_bridge(), add cleanup action (v6.18) 2. ✔ drm_bridge_get_prev_bridge() (v6.18) 3. ✔ drm_bridge_get_next_bridge() (v6.19) 4. ✔ drm_for_each_bridge_in_chain() (v6.19) 5. ✔ drm_bridge_connector_init (v6.19) 6. ✔ protect encoder bridge chain with a mutex (v7.2) 7. ➜ of_drm_find_bridge a. ✔ add of_drm_get_bridge() (v7.0), convert basic direct users (v7.0-v7.1) b. ✔ convert direct of_drm_get_bridge() users, part 2 (v7.0) c. ✔ convert direct of_drm_get_bridge() users, part 3 (v7.0) d. ✔ convert direct of_drm_get_bridge() users, part 4 (v7.1-v7.2) e. ➜ convert bridge-only drm_of_find_panel_or_bridge() users 8. drm_of_find_panel_or_bridge, *_of_get_bridge 9. ✔ enforce drm_bridge_add before drm_bridge_attach (v6.19) F. ✔ debugfs improvements 1. ✔ add top-level 'bridges' file (v6.16) 2. ✔ show refcount and list lingering bridges (v6.19) 2. … handle gracefully atomic updates during bridge removal A. ✔ Add drm_bridge_enter/exit() to protect device resources (v7.0) B. … protect private_obj removal from list C. ✔ Add drm_bridge_clear_and_put() (v7.1) 3. … DSI host-device driver interaction 4. ✔ removing the need for the "always-disconnected" connector 5. ✔ Migrate i.MX LCDIF driver to bridge-connector (v7.2) 6. … DRM bridge hotplug A. … Bridge hotplug management in the DRM core 1. … bridge-connector: attach encoder to the connector B. Device tree description [0] https://lore.kernel.org/lkml/20250206-hotplug-drm-bridge-v6-0-9d6f2c9c3058@bootlin.com/#t Signed-off-by: Luca Ceresoli --- Changes in v3: - patch 3, 8, 10: fixed ERR_PTR deref in the -ENODEV case, and removed Dmitry's R-by from those patches as they are changed - Added review trailers to the other patches - Link to v2: https://patch.msgid.link/20260428-drm-bridge-alloc-getput-panel_or_bridge-v2-0-4300744a1c47@bootlin.com Changes in v2: - Added patch to ignore ERR_PTR values in drm_bridge_get/put() - Changed API to return the bridge (or a ERR_PTR) in the return value, not as a double-pointer output parameter - Adapted all patches to the new API, dropped Dmitry's review tags as the patches are all modified - Removed bouncing addresses from Cc list - Link to v1: https://patch.msgid.link/20260413-drm-bridge-alloc-getput-panel_or_bridge-v1-0-acd01cd79a1f@bootlin.com --- Luca Ceresoli (11): drm/bridge: drm_bridge_get/put(): ignore ERR_PTR drm/bridge: add of_drm_get_bridge_by_endpoint() drm/msm/hdmi: switch to of_drm_get_bridge_by_endpoint() drm/hisilicon/kirin: switch to of_drm_get_bridge_by_endpoint() drm/bridge: chrontel-ch7033: switch to of_drm_get_bridge_by_endpoint() drm/bridge: lontium-lt9611uxc: switch to of_drm_get_bridge_by_endpoint() drm/bridge: lt9611: switch to of_drm_get_bridge_by_endpoint() drm/bridge: adv7511: switch to of_drm_get_bridge_by_endpoint() drm/bridge: lt8713sx: switch to of_drm_get_bridge_by_endpoint() drm: zynqmp_dp: switch to of_drm_get_bridge_by_endpoint() drm: of: forbid bridge-only calls to drm_of_find_panel_or_bridge() drivers/gpu/drm/bridge/adv7511/adv7511.h | 1 - drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 15 ++++---- drivers/gpu/drm/bridge/chrontel-ch7033.c | 28 +++++++-------- drivers/gpu/drm/bridge/lontium-lt8713sx.c | 10 +++--- drivers/gpu/drm/bridge/lontium-lt9611.c | 9 +++-- drivers/gpu/drm/bridge/lontium-lt9611uxc.c | 9 +++-- drivers/gpu/drm/drm_bridge.c | 53 ++++++++++++++++++++++++---- drivers/gpu/drm/drm_of.c | 26 +++++++------- drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c | 9 +++-- drivers/gpu/drm/msm/hdmi/hdmi.c | 11 ++++-- drivers/gpu/drm/xlnx/zynqmp_dp.c | 19 +++++----- include/drm/drm_bridge.h | 8 +++++ 12 files changed, 128 insertions(+), 70 deletions(-) --- base-commit: 6dbe0c5375e4f88c8d7c90790e0ea29d565b5d0a change-id: 20260410-drm-bridge-alloc-getput-panel_or_bridge-42501b38eaad Best regards, -- Luca Ceresoli