kernel/linux.git/drivers/gpu/drm/drm_bridge.c, branch v7.2-rc2

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

drm/bridge: drm_bridge_put(): ignore ERR_PTR

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

Most functions returning a struct drm_bridge pointer currently return a valid pointer or NULL, but this restricts their ability to return an error code as an ERR_PTR describing the error kind. In preparation to have new APIs that can return a struct drm_bridge pointer holding an ERR_PTR (and for those which already do) make drm_bridge_put() ignore ERR_PTR values, just like it ignores NULL pointers. This will avoid annoying error checking in many places and the risk of missing error checks. Suggested-by: Laurent Pinchart Link: https://lore.kernel.org/all/20260318152533.GA633439@killaraus.ideasonboard.com/ Suggested-by: Dmitry Baryshkov Link: https://lore.kernel.org/all/omlnswxukeqgnatzdvooaashgkfcacjevkvbkm6xt33itgua2k@jcmzll2w6kdq/ Reviewed-by: Dmitry Baryshkov Reviewed-by: Laurent Pinchart Link: https://patch.msgid.link/20260511-drm-bridge-alloc-getput-panel_or_bridge-v6-1-f61c9e498b3f@bootlin.com Signed-off-by: Luca Ceresoli

Merge drm/drm-next into drm-misc-next

2026-05-07T14:17:01+00:00

Merge drm-next to bring the drm_atomic_state renaming patch. Signed-off-by: Maxime Ripard

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: prefer drm_printf_indent() over inline \t

2026-04-29T10:50:33+00:00

We have a helper drm_printf_indent() for tab indenting the prints. It makes the actual strings more readable, and highlights the indented parts better in source. Reviewed-by: Chaitanya Kumar Borah Link: https://patch.msgid.link/20260408082211.3040194-2-jani.nikula@intel.com Signed-off-by: Jani Nikula

drm/bridge: prevent encoder chain changes in pre_enable/post_disable

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

Take the encoder chain mutex while iterating over the encoder chain in drm_atomic_bridge_chain_pre_enable() and drm_atomic_bridge_chain_post_disable() to ensure the lists won't change while being inspected. These functions have nested list_for_each_*() loops, which makes them complicated. list_for_each_entry_from() loops could be replaced by drm_for_each_bridge_in_chain_from(), but it would not work in a nested way in its current implementation. Besides, there is no "_reverse" variant of drm_for_each_bridge_in_chain_from(). Keep code simple and readable by explicitly locking around the outer loop. Thankfully there are no break or return points inside the loops, so the change is trivial and readable. Reviewed-by: Maxime Ripard Reviewed-by: Louis Chauvet Link: https://patch.msgid.link/20260324-drm-bridge-alloc-encoder-chain-mutex-v5-7-8bf786c5c7e6@bootlin.com Signed-off-by: Luca Ceresoli

drm/bridge: prevent encoder chain changes while iterating with list_for_each_entry_reverse()

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

These loops in drm_bridge.c iterate over the encoder chain using list_for_each_entry_reverse(), which does not prevent changes to the bridge chain while iterating over it. Take the encoder chain mutex while iterating to avoid chain changes while iterating. All the "simple" loops are converted. drm_atomic_bridge_chain_pre_enable() and drm_atomic_bridge_chain_post_disable() are handled by a separate commit. Reviewed-by: Louis Chauvet Link: https://patch.msgid.link/20260324-drm-bridge-alloc-encoder-chain-mutex-v5-6-8bf786c5c7e6@bootlin.com Signed-off-by: Luca Ceresoli

drm/bridge: prevent encoder chain changes while iterating with list_for_each_entry_from()

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

These loops in drm_bridge.c iterate over the encoder chain using list_for_each_entry_from(), which does not prevent changes to the bridge chain while iterating over it. Convert most of those loops to instead use drm_for_each_bridge_in_chain_from(), which locks the chain. This also simplifies code. All the "simple" loops are converted here. The only ones not touched are those in drm_atomic_bridge_chain_pre_enable() and drm_atomic_bridge_chain_post_disable(), because they have nested loops which are not well handled by drm_for_each_bridge_in_chain_from(). Those two functions are handled by a separate commit. Reviewed-by: Louis Chauvet Link: https://patch.msgid.link/20260324-drm-bridge-alloc-encoder-chain-mutex-v5-5-8bf786c5c7e6@bootlin.com Signed-off-by: Luca Ceresoli

drm/bridge: drm_bridge_attach: lock the encoder chain mutex during insertion

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

drm_bridge_attach() modifies the encoder bridge chain, so take a mutex around such operations to allow users of the chain to protect themselves from chain modifications while iterating. Reviewed-by: Maxime Ripard Reviewed-by: Louis Chauvet Link: https://patch.msgid.link/20260324-drm-bridge-alloc-encoder-chain-mutex-v5-3-8bf786c5c7e6@bootlin.com Signed-off-by: Luca Ceresoli