kernel/linux.git/include/drm/drm_bridge.h, branch v7.2-rc1

drm/bridge: add of_drm_get_bridge_by_endpoint()

2026-05-19T08:57:25+00:00

drm_of_find_panel_or_bridge() is widely used, but many callers pass NULL into the @panel or the @bridge arguments, thus making a very partial usage of this rather complex function. Besides, the bridge returned in @bridge is not refcounted, thus making this API unsafe when DRM bridge hotplug will be introduced. Solve both issues for the cases of calls to drm_of_find_panel_or_bridge() with a NULL @panel pointer by adding a new function that only looks for bridges (and is thus much simpler) and increments the refcount of the returned bridge. The new function is identical to drm_of_find_panel_or_bridge() except it: - handles bridge refcounting: uses of_drm_find_and_get_bridge() instead of of_drm_find_bridge() internally to return a refcounted bridge - is simpler to use: just takes no @panel parameter, returns the pointer in the return value instead of a double pointer argument - has a simpler implementation: it is equal to drm_of_find_panel_or_bridge() after removing the code that becomes dead when @panel == NULL Also add this function to drm_bridge.c and not drm_of.c because it returns bridges only. Reviewed-by: Dmitry Baryshkov Reviewed-by: Laurent Pinchart Link: https://patch.msgid.link/20260511-drm-bridge-alloc-getput-panel_or_bridge-v6-2-f61c9e498b3f@bootlin.com Signed-off-by: Luca Ceresoli

Merge tag 'drm-misc-next-2026-04-20' of https://gitlab.freedesktop.org/drm/misc/kernel into drm-next

2026-05-06T00:12:25+00:00

drm-misc-next for v7.1-rc1: UAPI Changes: - Expose per-client BO memory usage via fdinfo in amdxdna. (Hou) - Change the default priority of drm scheduler to fair. (Tvrtko) Cross-subsystem Changes: - Revert hugetlb support in udmabuf. (Gunthorpe) - Fix error in udmabuf with CONFIG_DMA_API_DEBUG(/ _SG). (Gavrilov) - Add Docbook for DRM_IOCTL_SYNCOBJ_EVENTFD, (Ser) clarify drm_bridge_get/put. (Tvrtko) - Change signature of drm_connector_attach_hdr_output_metadata_property. (Canal) - Use IOVA allocations in gpusvm and pagemap APIs. (Brost) - Fix tracepoints vs dma-fence lifetime. (Tvrtko) - Convert st-dma*.c tests to use kunit. (Gunthorpe) Core Changes: - Deduplicate counter and timestamp retrieval in vblank code. (Ville) - Parse AMD VSDB v3 in CTA extension blocks, and use it in amdgpu. (Chen) - Prevent bridge and encoder chain changes at inopportune times. (Ceresoli) - Map the run queue 1:1 to the drm scheduler. (Tvrtko) Driver Changes: - Assorted bugfixes and (documentation) updates to rockchip, bridge/synopsis, panfrost, tidss, accel/qaic, tilcdc, vc4, ast, imagination, panthor, renesas, accel/amdxdna, msxfb, bridge/imx8mp, nouveau. bridge/analogix_dp, bridge/exynos_dp, omap. - Add support for CSW PNB601LS1-2, LGD LP116WHA-SPB1, panels. - Add support for a lot of waveshare panels (Baryshkov) - Support for AIE4 devices in accel/wamdxdna. (Zhang) - Enable support for GEM shrinking in panthor. (Goel/Brezillon) - Runtime Power Management is added to v3d. (Canal) - Allow panel probing and use the panel bridge helper in analogix_dp. (Ding) - Support XRGB1555 and C8 in mgag and XRGB1555 in ast. (Zimmermann) From: Maarten Lankhorst Link: https://patch.msgid.link/bf31b1a1-951b-4f60-b226-22e8c083697d@linux.intel.com Signed-off-by: Dave Airlie

drm: Rename struct drm_atomic_state to drm_atomic_commit

2026-05-04T04:05:04+00:00

The KMS framework uses two slightly different definitions for the state concept. For a given object (plane, CRTC, encoder, etc., so drm_$OBJECT_state), the state is the entire state of that object. However, at the device level, drm_atomic_state refers to a state update for a limited number of objects. Thus, drm_atomic_state isn't the entire device state, but only the full state of some objects in that device. This has been an endless source of confusion and thus bugs. We can rename the drm_atomic_state structure to drm_atomic_commit to make it less confusing. This patch was created using: rg -l drm_atomic_state | \ xargs sed -i 's/drm_atomic_state/drm_atomic_commit/g; s/drm_atomic_commit_helper/drm_atomic_state_helper/g' mv drivers/gpu/drm/tests/drm_atomic_state_test.c drivers/gpu/drm/tests/drm_atomic_commit_test.c Acked-by: Simona Vetter Acked-by: Thomas Zimmermann Acked-by: Jani Nikula Reviewed-by: Luca Ceresoli Tested-by: Luca Ceresoli Signed-off-by: Maxime Ripard Signed-off-by: Dave Airlie Link: https://patch.msgid.link/20260427-drm-drm-atomic-update-v4-1-c0e713bfdf25@kernel.org

drm/bridge: lock the encoder chain in scoped for_each loops

2026-04-16T07:08:42+00:00

drm_for_each_bridge_in_chain_scoped() and drm_for_each_bridge_in_chain_from() currently get/put the bridge at each iteration. But they don't protect the encoder chain, so it could change (bridges added/removed) while some code is iterating over the list itself. Such code can then derail on incorrect pointers. To make iterations safe, augment these for_each macros to lock the encoder chain mutex at the beginning and unlock it at the end of the loop (be it at the end of the list, or earlier due to a 'break' or 'return' statement). This change requires more operations when starting and ending the loop. To avoid making the macros even more complex, move these operations to helper functions. Also remname some of the existing helper functions for consistency. Reviewed-by: Louis Chauvet Link: https://patch.msgid.link/20260324-drm-bridge-alloc-encoder-chain-mutex-v5-4-8bf786c5c7e6@bootlin.com Signed-off-by: Luca Ceresoli

drm/display: hdmi: Use drm_output_color_format instead of hdmi_colorspace

2026-03-24T12:54:35+00:00

The hdmi_colorspace enum was defined to represent the colorspace value of the HDMI infoframes. It was later used by some HDMI drivers to express the output format they should be setting up. During the introduction of the HDMI helpers, it then was used to represent it in the drm_connector_hdmi_state structure. However, it's always been somewhat redundant with the DRM_COLOR_FORMAT_* defines, and now with the drm_output_color_format enum. Let's consolidate around drm_output_color_format in drm_connector_hdmi_state to facilitate the current effort to provide a global output format selection mechanism. Acked-by: Jani Nikula Reviewed-by: Nicolas Frattaroli Reviewed-by: Dmitry Baryshkov Link: https://lore.kernel.org/r/20260305-drm-rework-color-formats-v3-14-f3935f6db579@kernel.org Signed-off-by: Maxime Ripard

drm/bridge: add drm_bridge_clear_and_put()

2026-03-20T10:02:12+00:00

Drivers having a struct drm_bridge pointer pointing to a bridge in many cases hold that reference until the owning device is removed. In those cases the reference to the bridge can be put in the .remove callback (possibly using devm actions) or in the .destroy func (possibly with the help of struct drm_bridge::next_bridge). At those moments the driver should not be operating anymore and won't dereference the bridge pointer after it is put. However there are cases when drivers need to stop holding a reference to a bridge even when their device is not being removed. This is the case for bridge hot-unplug, when a bridge is removed but the previous entity (bridge or encoder) is staying. In such case the "previous entity" needs to put it but cannot do it via devm or .destroy, because it is not being removed. The easy way to dispose of such pointer is: drm_bridge_put(my_priv->some_bridge); my_priv->some_bridge = NULL; However this is risky because there is a time window between the two lines where the reference is put, and thus the bridge could be deallocated, but the pointer is still assigned. If other functions of the same driver were invoked concurrently they might dereference my_priv->some_bridge during that window, resulting in use-after-free. A correct solution is to clear the pointer before putting the reference, but that needs a temporary variable: struct drm_bridge *temp = my_priv->some_bridge; my_priv->some_bridge = NULL; drm_bridge_put(temp); This solution is however annoying to write, so the incorrect version might still sneak in. Add a simple, easy to use function to put a bridge after setting its pointer to NULL in the correct way. Acked-by: Maxime Ripard Link: https://patch.msgid.link/20260310-drm-bridge-atomic-vs-remove-clear_and_put-v2-1-51fe222f3cf0@bootlin.com Signed-off-by: Luca Ceresoli

BackMerge tag 'v6.19-rc7' into drm-next

2026-01-28T02:44:28+00:00

Linux 6.19-rc7 This is needed for msm and rust trees. Signed-off-by: Dave Airlie

drm/bridge: refactor HDMI InfoFrame callbacks

2026-01-19T11:11:46+00:00

Having only a single set of callbacks, hdmi_clear_infoframe and hdmi_write_infoframe, bridge drivers don't have an easy way to signal to the DRM framework, which InfoFrames are actually supported by the hardware and by the driver and which are not. Also, it makes it extremely easy for HDMI bridge drivers to skip implementing the seemingly required InfoFrames (e.g. HDMI VSI). Last, but not least, those callbacks take a single 'type' parameter, which makes it impossible to implement support for multiple VSIs (which will be required once we start working on HDMI Forum VSI). Split the callbacks into a per-InfoFrame-kind pairs, letting the bridge drivers actually signal supported features. The implementation follows the overall drm_bridge design, where the bridge has a single drm_bridge_funcs implementation and signals, which functions are to be called using the drm_bridge->ops flags. The AVI and HDMI VSI are assumed to be required for a normal HDMI operation (with the drivers getting a drm_warn_once() stub implementation if one is missing). The Audio InfoFrame is handled by the existing DRM_BRIDGE_OP_HDMI_AUDIO, while the SPD and HDR DRM InfoFrames got new drm_bridge_ops values. Acked-by: Maxime Ripard Link: https://patch.msgid.link/20260107-limit-infoframes-2-v4-5-213d0d3bd490@oss.qualcomm.com Signed-off-by: Dmitry Baryshkov

Revert "drm/atomic-helper: Re-order bridge chain pre-enable and post-disable"

2026-01-03T19:06:54+00:00

This reverts commit c9b1150a68d9362a0827609fc0dc1664c0d8bfe1. Changing the enable/disable sequence has caused regressions on multiple platforms: R-Car, MCDE, Rockchip. A series (see link below) was sent to fix these, but it was decided that it's better to revert the original patch and change the enable/disable sequence only in the tidss driver. Reverting this commit breaks tidss's DSI and OLDI outputs, which will be fixed in the following commits. Signed-off-by: Tomi Valkeinen Link: https://lore.kernel.org/all/20251202-mcde-drm-regression-thirdfix-v6-0-f1bffd4ec0fa%40kernel.org/ Fixes: c9b1150a68d9 ("drm/atomic-helper: Re-order bridge chain pre-enable and post-disable") Cc: stable@vger.kernel.org # v6.17+ Reviewed-by: Aradhya Bhatia Reviewed-by: Maxime Ripard Reviewed-by: Linus Walleij Tested-by: Linus Walleij Signed-off-by: Linus Walleij Link: https://patch.msgid.link/20251205-drm-seq-fix-v1-1-fda68fa1b3de@ideasonboard.com

drm/bridge: add next_bridge pointer to struct drm_bridge

2025-12-30T09:11:33+00:00

Many bridge drivers store a next_bridge pointer in their private data and use it for attach and sometimes other purposes. This is going to be risky when bridge hot-unplug is used. Considering this example scenario: 1. pipeline: encoder --> bridge A --> bridge B --> bridge C 2. encoder takes a reference to bridge B 3. bridge B takes a next_bridge reference to bridge C 4. encoder calls (bridge B)->b_foo(), which in turns references next_bridge, e.g.: b_foo() { bar(b->next_bridge); } If bridges B and C are removed, bridge C can be freed but B is still allocated because the encoder holds a reference to B. So when step 4 happens, 'b->next-bridge' would be a use-after-free. Calling drm_bridge_put() in the B bridge .remove function does not solve the problem as it leaves a (potentially long) risk window between B removal and the final deallocation of B. A safe moment to put the B reference is in __drm_bridge_free(), when the last reference has been put. This can be done by drivers in the .destroy func. However to avoid the need for so many drivers to implement a .destroy func, just offer a next_bridge pointer to all bridges that is automatically put it in __drm_bridge_free(), exactly when the .destroy func is called. Suggested-by: Maxime Ripard Link: https://lore.kernel.org/all/20251201-thick-jasmine-oarfish-1eceb0@houat/ Reviewed-by: Maxime Ripard Link: https://patch.msgid.link/20251216-drm-bridge-alloc-getput-drm_of_find_bridge-v3-6-b5165fab8058@bootlin.com Signed-off-by: Luca Ceresoli