From cf3bef95e1014233cb1ce89da8cfa5cd22e7412c Mon Sep 17 00:00:00 2001 From: Andrea Merello Date: Thu, 25 Aug 2016 11:04:32 +0200 Subject: [PATCH] drm/bridge: introduce bridge detaching mechanism 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. Few other kerneldocs fixes around there are included. Suggested-by: Daniel Vetter Suggested-by: Lucas Stach Signed-off-by: Andrea Merello Cc: Archit Taneja Cc: David Airlie Cc: Daniel Vetter Cc: Lucas Stach Signed-off-by: Archit Taneja Link: http://patchwork.freedesktop.org/patch/msgid/1472115874-6219-1-git-send-email-andrea.merello@gmail.com --- drivers/gpu/drm/drm_bridge.c | 29 +++++++++++++++++++++++++++-- include/drm/drm_crtc.h | 26 +++++++++++++++++++++++++- 2 files changed, 52 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c index 255543086590..484046664d6c 100644 --- a/drivers/gpu/drm/drm_bridge.c +++ b/drivers/gpu/drm/drm_bridge.c @@ -98,11 +98,11 @@ EXPORT_SYMBOL(drm_bridge_remove); * @dev: DRM device * @bridge: bridge control structure * - * called by a kms driver to link one of our encoder/bridge to the given + * Called by a kms driver to link one of our encoder/bridge to the given * bridge. * * Note that setting up links between the bridge and our encoder/bridge - * objects needs to be handled by the kms driver itself + * objects needs to be handled by the kms driver itself. * * RETURNS: * Zero on success, error code on failure @@ -124,6 +124,31 @@ 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 * diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h index 3fa0275e509f..bb214a114329 100644 --- a/include/drm/drm_crtc.h +++ b/include/drm/drm_crtc.h @@ -1118,11 +1118,32 @@ struct drm_plane { /** * struct drm_bridge_funcs - drm_bridge control functions - * @attach: Called during drm_bridge_attach */ struct drm_bridge_funcs { + /** + * @attach: + * + * This callback is invoked whenever our bridge is being attached to a + * &drm_encoder. + * + * The attach callback is optional. + * + * 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 from a + * &drm_encoder. + * + * The detach callback is optional. + */ + void (*detach)(struct drm_bridge *bridge); + /** * @mode_fixup: * @@ -1137,6 +1158,8 @@ struct drm_bridge_funcs { * this function passes all other callbacks must succeed for this * configuration. * + * The mode_fixup callback is optional. + * * NOTE: * * This function is called in the check phase of atomic modesets, which @@ -2426,6 +2449,7 @@ 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, -- 2.20.1