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drm/bridge: introduce bridge detaching mechanism

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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 <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>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Link: http://patchwork.freedesktop.org/patch/msgid/1472115874-6219-1-git-send-email-andrea.merello@gmail.com
This commit is contained in:
Andrea Merello 2016-08-25 11:04:32 +02:00 committed by Archit Taneja
parent 6dcf0de7ef
commit cf3bef95e1
2 changed files with 52 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

29
drivers/gpu/drm/drm_bridge.c
View File

@ -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
*

26
include/drm/drm_crtc.h
View File

@ -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,