Up to now, once a bridge has been attached to a DRM device, it cannot be undone.
In particular you couldn't rmmod/insmod a DRM driver that uses a bridge, because the bridge would remain bound to the first (dead) driver instance.
This patch fixes this by introducing drm_encoder_detach() and a ->detach callback in drm_bridge_funcs for the bridge to be notified about detaches.
It's DRM/KMS driver responsibility to call drm_encoder_detach().
While adding the bridge detach callback, with its kerneldoc, I also added kerneldoc for attach callback.
Suggested-by: Daniel Vetter daniel@ffwll.ch Suggested-by: Lucas Stach l.stach@pengutronix.de Signed-off-by: Andrea Merello andrea.merello@gmail.com Cc: Archit Taneja architt@codeaurora.org Cc: David Airlie airlied@linux.ie Cc: Daniel Vetter daniel@ffwll.ch Cc: Lucas Stach l.stach@pengutronix.de --- drivers/gpu/drm/drm_bridge.c | 26 ++++++++++++++++++++++++++ include/drm/drm_crtc.h | 17 +++++++++++++++++ 2 files changed, 43 insertions(+)
diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c index 2555430..a77b3e0 100644 --- a/drivers/gpu/drm/drm_bridge.c +++ b/drivers/gpu/drm/drm_bridge.c @@ -125,6 +125,32 @@ int drm_bridge_attach(struct drm_device *dev, struct drm_bridge *bridge) EXPORT_SYMBOL(drm_bridge_attach);
/** + * drm_bridge_detach - deassociate given bridge from its DRM device + * + * @bridge: bridge control structure + * + * called by a kms driver to unlink the given bridge from its DRM device + * + * Note that tearing down links between the bridge and our encoder/bridge + * objects needs to be handled by the kms driver itself + * + */ +void drm_bridge_detach(struct drm_bridge *bridge) +{ + if (WARN_ON(!bridge)) + return; + + if (WARN_ON(!bridge->dev)) + return; + + if (bridge->funcs->detach) + bridge->funcs->detach(bridge); + + bridge->dev = NULL; +} +EXPORT_SYMBOL(drm_bridge_detach); + +/** * DOC: bridge callbacks * * The &drm_bridge_funcs ops are populated by the bridge driver. The DRM diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h index b618b50..5e25e23 100644 --- a/include/drm/drm_crtc.h +++ b/include/drm/drm_crtc.h @@ -1765,9 +1765,25 @@ struct drm_plane { * @attach: Called during drm_bridge_attach */ struct drm_bridge_funcs { + /** + * @attach: + * + * This callback is invoked whenever our bridge is being attached. + * + * RETURNS: + * + * Zero on success, error code on failure + */ int (*attach)(struct drm_bridge *bridge);
/** + * @detach: + * + * This callback is invoked whenever our bridge is being detached. + */ + void (*detach)(struct drm_bridge *bridge); + + /** * @mode_fixup: * * This callback is used to validate and adjust a mode. The paramater @@ -3196,6 +3212,7 @@ extern int drm_bridge_add(struct drm_bridge *bridge); extern void drm_bridge_remove(struct drm_bridge *bridge); extern struct drm_bridge *of_drm_find_bridge(struct device_node *np); extern int drm_bridge_attach(struct drm_device *dev, struct drm_bridge *bridge); +extern void drm_bridge_detach(struct drm_bridge *bridge);
bool drm_bridge_mode_fixup(struct drm_bridge *bridge, const struct drm_display_mode *mode,