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| author | Luca Ceresoli <luca.ceresoli@bootlin.com> | 2025-03-26 18:47:36 +0100 |
|---|---|---|
| committer | Louis Chauvet <louis.chauvet@bootlin.com> | 2025-04-07 11:38:04 +0200 |
| commit | 30d1b37d4c022b5e6c164c090a60a3be1a66876e (patch) | |
| tree | a2ae4c064d59d7a6d996a639319237588172ace0 /include | |
| parent | 0cc6aadd7fc1e629b715ea3d1ba537ef2da95eec (diff) | |
drm/bridge: add support for refcounting
DRM bridges are currently considered as a fixed element of a DRM card, and
thus their lifetime is assumed to extend for as long as the card
exists. New use cases, such as hot-pluggable hardware with video bridges,
require DRM bridges to be added to and removed from a DRM card without
tearing the card down. This is possible for connectors already (used by DP
MST), it is now needed for DRM bridges as well.
As a first preliminary step, make bridges reference-counted to allow a
struct drm_bridge (along with the private driver structure embedding it) to
stay allocated even after the driver has been removed, until the last
reference is put.
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Reviewed-by: Maxime Ripard <mripard@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20250326-drm-bridge-refcount-v9-2-5e0661fe1f84@bootlin.com
Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
Diffstat (limited to 'include')
| -rw-r--r-- | include/drm/drm_bridge.h | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h index a59277674d5a..df9bbf6fd1fb 100644 --- a/include/drm/drm_bridge.h +++ b/include/drm/drm_bridge.h @@ -840,6 +840,18 @@ struct drm_bridge { const struct drm_bridge_timings *timings; /** @funcs: control functions */ const struct drm_bridge_funcs *funcs; + + /** + * @container: Pointer to the private driver struct embedding this + * @struct drm_bridge. + */ + void *container; + + /** + * @refcount: reference count of users referencing this bridge. + */ + struct kref refcount; + /** @driver_private: pointer to the bridge driver's internal context */ void *driver_private; /** @ops: bitmask of operations supported by the bridge */ @@ -941,6 +953,9 @@ drm_priv_to_bridge(struct drm_private_obj *priv) return container_of(priv, struct drm_bridge, base); } +struct drm_bridge *drm_bridge_get(struct drm_bridge *bridge); +void drm_bridge_put(struct drm_bridge *bridge); + void *__devm_drm_bridge_alloc(struct device *dev, size_t size, size_t offset, const struct drm_bridge_funcs *funcs); @@ -951,6 +966,10 @@ void *__devm_drm_bridge_alloc(struct device *dev, size_t size, size_t offset, * @member: the name of the &drm_bridge within @type * @funcs: callbacks for this bridge * + * The reference count of the returned bridge is initialized to 1. This + * reference will be automatically dropped via devm (by calling + * drm_bridge_put()) when @dev is removed. + * * Returns: * Pointer to new bridge, or ERR_PTR on failure. */ |