kernel/linux.git/drivers/gpu/drm/drm_bridge.c, branch v6.18.22

drm/debugfs: bridges_show: show refcount

2025-09-02T09:18:55+00:00

Now that bridges are refcounted, exposing the refcount in debugfs can be useful. Suggested-by: Dmitry Baryshkov Reviewed-by: Maxime Ripard Link: https://lore.kernel.org/r/20250819-drm-bridge-debugfs-removed-v7-1-970702579978@bootlin.com Signed-off-by: Luca Ceresoli

Merge tag 'drm-misc-next-2025-08-14' of https://gitlab.freedesktop.org/drm/misc/kernel into drm-next

2025-08-18T21:02:30+00:00

drm-misc-next for v6.18: UAPI Changes: - Add DRM_IOCTL_GEM_CHANGE_HANDLE for reassigning GEM handles - Document DRM_MODE_PAGE_FLIP_EVENT Cross-subsystem Changes: fbcon: - Add missing declarations in fbcon.h Core Changes: bridge: - Fix ref counting panel: - Replace and remove mipi_dsi_generic_write_{seq/_chatty}() sched: - Fixes Rust: - Drop Opaque<> from ioctl arguments Driver Changes: amdxdma: - Support buffers allocated by user space - Streamline PM interfaces - Fixes bridge: - cdns-dsi: Various improvements to mode setting - Support Solomon SSD2825 plus DT bindings - Support Waveshare DSI2DPI plus DT bindings gud: - Fixes ivpu: - Fixes nouveau: - Use GSP firmware by default - Fixes panel: - panel-edp: Support mt8189 Chromebooks; Support BOE NV140WUM-N64; Support SHP LQ134Z1; Fixes - panel-simple: Support Olimex LCD-OLinuXino-5CTS plus DT bindings - Support Samsung AMS561RA01 - Support Hydis HV101HD1 plus DT bindings panthor: - Print task/pid on errors - Fixes renesas: - convert to RUNTIME_PM_OPS repaper: - Use shadow-plane helpers rocket: - Add driver for Rockchip NPU plus DT bindings sharp-memory: - Use shadow-plane helpers simpledrm: - Use of_reserved_mem_region_to_resource() helper tidss: - Use crtc_ fields for programming display mode - Remove other drivers from aperture v3d: - Support querying nubmer of GPU resets for KHR_robustness vmwgfx: - Fixes Signed-off-by: Dave Airlie From: Thomas Zimmermann Link: https://lore.kernel.org/r/20250814072454.GA18104@linux.fritz.box

drm/bridge: Describe the newly introduced drm_connector parameter for drm_bridge_detect

2025-08-04T07:39:21+00:00

This fix the make htmldocs warnings: drivers/gpu/drm/drm_bridge.c:1242: warning: Function parameter or struct member 'connector' not described in 'drm_bridge_detect' Fixes: 5d156a9c3d5e ("drm/bridge: Pass down connector to drm bridge detect hook") Signed-off-by: Andy Yan Reviewed-by: Dmitry Baryshkov Link: https://lore.kernel.org/r/20250716125602.3166573-1-andyshrk@163.com Signed-off-by: Dmitry Baryshkov

drm/bridge: select_bus_fmt_recursive(): put the bridge obtained by drm_bridge_get_prev_bridge()

2025-07-23T11:03:53+00:00

The bridge returned by drm_bridge_get_prev_bridge() is refcounted. Put it when done. select_bus_fmt_recursive() has several return points, and ensuring drm_bridge_put() is always called in the right place would be error-prone (especially with future changes to the select_bus_fmt_recursive() code) and make code uglier. Instead use a scope-based free, which is future-proof and a lot cleaner. Reviewed-by: Maxime Ripard Link: https://lore.kernel.org/r/20250709-drm-bridge-alloc-getput-drm_bridge_get_prev_bridge-v1-2-34ba6f395aaa@bootlin.com Signed-off-by: Luca Ceresoli

drm/bridge: Pass down connector to drm bridge detect hook

2025-07-14T15:23:18+00:00

In some application scenarios, we hope to get the corresponding connector when the bridge's detect hook is invoked. In most cases, we can get the connector by drm_atomic_get_connector_for_encoder if the encoder attached to the bridge is enabled, however there will still be some scenarios where the detect hook of the bridge is called but the corresponding encoder has not been enabled yet. For instance, this occurs when the device is hot plug in for the first time. Since the call to bridge's detect is initiated by the connector, passing down the corresponding connector directly will make things simpler. Signed-off-by: Andy Yan Reviewed-by: Dmitry Baryshkov Link: https://lore.kernel.org/r/20250703125027.311109-3-andyshrk@163.com [DB: added the chunk to the cdn-dp driver] Signed-off-by: Dmitry Baryshkov

drm/bridge: add warning for bridges not using devm_drm_bridge_alloc()

2025-06-26T13:05:20+00:00

To the best of my knowledge, all drivers in the mainline kernel adding a DRM bridge are now converted to using devm_drm_bridge_alloc() for allocation and initialization. Among others this ensures initialization of the bridge refcount, allowing dynamic allocation lifetime. devm_drm_bridge_alloc() is now mandatory for all new bridges. Code using the old pattern ([devm_]kzalloc + filling the struct fields + drm_bridge_add) is not allowed anymore. Any drivers that might have been missed during the conversion, patches in flight towards mainline and out-of-tre drivers still using the old pattern will already be caught by a warning looking like: ------------[ cut here ]------------ refcount_t: addition on 0; use-after-free. WARNING: CPU: 2 PID: 83 at lib/refcount.c:25 refcount_warn_saturate+0x120/0x148 [...] Call trace: refcount_warn_saturate+0x120/0x148 (P) drm_bridge_get.part.0+0x70/0x98 [drm] drm_bridge_add+0x34/0x108 [drm] sn65dsi83_probe+0x200/0x480 [ti_sn65dsi83] [...] This warning comes from the refcount code and happens because drm_bridge_add() is increasing the refcount, which is uninitialized and thus initially zero. Having a warning and the corresponding stack trace is surely useful, but the warning text does not clarify the root problem nor how to fix it. Add a DRM_WARN() just before increasing the refcount, so the log will be much more readable: [drm] DRM bridge corrupted or not allocated by devm_drm_bridge_alloc() ------------[ cut here ]------------ refcount_t: addition on 0; use-after-free. [...etc...] A DRM_WARN is used because drm_warn and drm_WARN require a struct drm_device pointer which is not yet available when adding a bridge. Do not print the dev_name() in the warning because struct drm_bridge has no pointer to the struct device. The affected driver should be easy to catch based on the following stack trace however. Reviewed-by: Maxime Ripard Link: https://lore.kernel.org/r/20250620-drm-bridge-alloc-getput-drm-bridge-c-v9-3-ca53372c9a84@bootlin.com Signed-off-by: Luca Ceresoli

drm/bridge: get/put the bridge reference in drm_bridge_attach/detach()

2025-06-26T13:05:20+00:00

drm_bridge_attach() adds the bridge to the encoder chain, so take a reference for that. Vice versa in drm_bridge_detach(). Reviewed-by: Maxime Ripard Link: https://lore.kernel.org/r/20250620-drm-bridge-alloc-getput-drm-bridge-c-v9-2-ca53372c9a84@bootlin.com Signed-off-by: Luca Ceresoli

drm/bridge: get/put the bridge reference in drm_bridge_add/remove()

2025-06-26T13:05:20+00:00

drm_bridge_add() adds the bridge to the global bridge_list, so take a reference for that. Vice versa in drm_bridge_remove(). Reviewed-by: Maxime Ripard Link: https://lore.kernel.org/r/20250620-drm-bridge-alloc-getput-drm-bridge-c-v9-1-ca53372c9a84@bootlin.com Signed-off-by: Luca Ceresoli

drm/bridge: Include

2025-06-16T07:02:25+00:00

Fix compile-time warnings drivers/gpu/drm/bridge/analogix/analogix-i2c-dptx.c: warning: EXPORT_SYMBOL() is used, but #include is missing drivers/gpu/drm/bridge/analogix/analogix_dp_core.c: warning: EXPORT_SYMBOL() is used, but #include is missing drivers/gpu/drm/bridge/aux-bridge.c: warning: EXPORT_SYMBOL() is used, but #include is missing drivers/gpu/drm/bridge/aux-hpd-bridge.c: warning: EXPORT_SYMBOL() is used, but #include is missing drivers/gpu/drm/bridge/imx/imx-legacy-bridge.c: warning: EXPORT_SYMBOL() is used, but #include is missing drivers/gpu/drm/bridge/panel.c: warning: EXPORT_SYMBOL() is used, but #include is missing drivers/gpu/drm/bridge/samsung-dsim.c: warning: EXPORT_SYMBOL() is used, but #include is missing drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c: warning: EXPORT_SYMBOL() is used, but #include is missing drivers/gpu/drm/bridge/synopsys/dw-hdmi.c: warning: EXPORT_SYMBOL() is used, but #include is missing drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c: warning: EXPORT_SYMBOL() is used, but #include is missing drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi2.c: warning: EXPORT_SYMBOL() is used, but #include is missing drivers/gpu/drm/drm_bridge.c: warning: EXPORT_SYMBOL() is used, but #include is missing drivers/gpu/drm/drm_bridge_helper.c: warning: EXPORT_SYMBOL() is used, but #include is missing Signed-off-by: Thomas Zimmermann Fixes: a934a57a42f6 ("scripts/misc-check: check missing #include when W=1") Reviewed-by: André Almeida Cc: Masahiro Yamada Cc: Nathan Chancellor Link: https://lore.kernel.org/r/20250612121633.229222-4-tzimmermann@suse.de

drm/bridge: add a .destroy func

2025-06-06T13:50:22+00:00

Some users of DRM bridges may need to execute specific code just before deallocation. As of now the only known user would be KUnit tests. Suggested-by: Maxime Ripard Acked-by: Maxime Ripard Signed-off-by: Luca Ceresoli Link: https://lore.kernel.org/r/20250606-drm-bridge-alloc-doc-test-v9-2-b5bf7b43ed92@bootlin.com Signed-off-by: Maxime Ripard