drm/bridge: add support for refcounting

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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>

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Luca Ceresoli 2025-03-26 18:47:36 +01:00 • committed by Louis Chauvet

parent 0cc6aadd7f

commit 30d1b37d4c

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2 changed files with 81 additions and 1 deletions

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63

drivers/gpu/drm/drm_bridge.c

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19

include/drm/drm_bridge.h

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