Commit cf3bef95 authored by Andrea Merello's avatar Andrea Merello Committed by Archit Taneja
Browse files

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: default avatarDaniel Vetter <daniel@ffwll.ch>
Suggested-by: default avatarLucas Stach <l.stach@pengutronix.de>
Signed-off-by: default avatarAndrea 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: default avatarArchit Taneja <architt@codeaurora.org>
Link: http://patchwork.freedesktop.org/patch/msgid/1472115874-6219-1-git-send-email-andrea.merello@gmail.com
parent 6dcf0de7

drivers/gpu/drm/drm_bridge.c

+27 −2
Original line number Diff line number Diff line
@@ -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

 *

include/drm/drm_crtc.h

+25 −1
Original line number Diff line number Diff line
@@ -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,

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