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bh=dkhIW77Yh2FAE70dgLvbC4t3pinG2sG9dM7gIueWcBs=; b=TzZlKvGu45dA/PBtvB/PyfKPxkyj37e6mUnL2ht76EwC3uc7w7h2g3gVTRhMtZB0wK3QhW bGQkdEfhYwHHZ8B9Qkiajss0FyFXh8Iw+KTcAoxkaVluDkxZTIFLiIuGX4ke4OoYkDRyIy +JzrP5hjQtkwFSkvljWjxqYTHwcMfY8X2dknhhgusD1ITHMSQMYlQKQM+n9dzaXcjNMo07 XD7tsBMfLeq4kZJaVhimAxB92gajaO6hmCKr/jZowmqhJp1TrfqCCOqpFDyAaKfWghheg3 JufT9qSk4JB9ZATa40SCvLew1tIKQtLqhMzo4LDrsInuphkgqtwTn6mmLZa4eQ== From: Luca Ceresoli Subject: [PATCH v2 00/11] drm/bridge: handle refcounting for bridge-only callers of drm_of_find_panel_or_bridge() Date: Tue, 28 Apr 2026 11:15:46 +0200 Message-Id: <20260428-drm-bridge-alloc-getput-panel_or_bridge-v2-0-4300744a1c47@bootlin.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit X-B4-Tracking: v=1; b=H4sIAMJ68GkC/42Oyw6CMBREf4V0bU1b8LnyPwwhfVzgGmhJW4iG8 O8W1L3Lk5nMmZkE8AiBXLOZeJgwoLMJxC4jupW2AYomMRFMHFnBGTW+p8qjSYnsOqdpA3EYIx2 kha5yvvqGhTgwrvIzSGlIWhs81PjcTPfyw2FUD9BxnV8bLYbo/Gu7MvG197Pmf1snThmV2jCuz ekieX1TzsUO7V67npTLsrwBcY5hW/IAAAA= X-Change-ID: 20260410-drm-bridge-alloc-getput-panel_or_bridge-42501b38eaad To: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Rob Clark , Dmitry Baryshkov , Abhinav Kumar , Jessica Zhang , Sean Paul , Marijn Suijten , Tian Tao , Xinwei Kong , Sumit Semwal , John Stultz , Andrzej Hajda , Neil Armstrong , Robert Foss , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , 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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260428_021612_670284_37AA81B5 X-CRM114-Status: GOOD ( 12.17 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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 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 | 11 +++--- 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 | 7 ++-- drivers/gpu/drm/xlnx/zynqmp_dp.c | 13 ++++--- include/drm/drm_bridge.h | 8 +++++ 12 files changed, 115 insertions(+), 69 deletions(-) --- base-commit: 6dbe0c5375e4f88c8d7c90790e0ea29d565b5d0a change-id: 20260410-drm-bridge-alloc-getput-panel_or_bridge-42501b38eaad Best regards, -- Luca Ceresoli