Add an atomic variant of the ->detect callback and a new helper to call the hook while passing an optional drm_modeset_acquire_ctx reference.
When both ->detect_ctx and ->detect are defined, the latter is ignored. If acquire_ctx is unset, the function takes care of the locking, while also handling EDEADLK. Signed-off-by: Cristian Ciocaltea <[email protected]> --- drivers/gpu/drm/drm_bridge.c | 58 ++++++++++++++++++++++++++++++++++++++++++++ include/drm/drm_bridge.h | 30 +++++++++++++++++++++++ 2 files changed, 88 insertions(+) diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c index 8f355df883d8..1fe03bcf2fc1 100644 --- a/drivers/gpu/drm/drm_bridge.c +++ b/drivers/gpu/drm/drm_bridge.c @@ -1280,6 +1280,64 @@ drm_bridge_detect(struct drm_bridge *bridge, struct drm_connector *connector) } EXPORT_SYMBOL_GPL(drm_bridge_detect); +/** + * drm_bridge_detect_ctx - check if anything is attached to the bridge output + * @bridge: bridge control structure + * @connector: attached connector + * @ctx: acquire_ctx, or NULL to let this function handle locking + * + * If the bridge supports output detection, as reported by the + * DRM_BRIDGE_OP_DETECT bridge ops flag, call &drm_bridge_funcs.detect_ctx + * or &drm_bridge_funcs.detect for the bridge and return the connection status. + * Otherwise return connector_status_unknown. + * + * When both @ctx and &drm_bridge_funcs.detect_ctx are not set, this helper + * function is equivalent to drm_bridge_detect() above. + * + * RETURNS: + * The detection status on success, or connector_status_unknown if the bridge + * doesn't support output detection. + * If @ctx is set, it might also return -EDEADLK. + */ +int drm_bridge_detect_ctx(struct drm_bridge *bridge, + struct drm_connector *connector, + struct drm_modeset_acquire_ctx *ctx) +{ + if (!(bridge->ops & DRM_BRIDGE_OP_DETECT)) + return connector_status_unknown; + + if (bridge->funcs->detect_ctx) { + struct drm_modeset_acquire_ctx br_ctx; + int ret; + + if (ctx) + return bridge->funcs->detect_ctx(bridge, connector, ctx); + + drm_modeset_acquire_init(&br_ctx, 0); +retry: + ret = drm_modeset_lock(&connector->dev->mode_config.connection_mutex, + &br_ctx); + if (!ret) + ret = bridge->funcs->detect_ctx(bridge, connector, &br_ctx); + + if (ret == -EDEADLK) { + drm_modeset_backoff(&br_ctx); + goto retry; + } + + if (ret < 0) + ret = connector_status_unknown; + + drm_modeset_drop_locks(&br_ctx); + drm_modeset_acquire_fini(&br_ctx); + + return ret; + } + + return bridge->funcs->detect(bridge, connector); +} +EXPORT_SYMBOL_GPL(drm_bridge_detect_ctx); + /** * drm_bridge_get_modes - fill all modes currently valid for the sink into the * @connector diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h index 0ff7ab4aa868..e11a1b39ef33 100644 --- a/include/drm/drm_bridge.h +++ b/include/drm/drm_bridge.h @@ -664,6 +664,33 @@ struct drm_bridge_funcs { enum drm_connector_status (*detect)(struct drm_bridge *bridge, struct drm_connector *connector); + /** + * @detect_ctx: + * + * Check if anything is attached to the bridge output. + * + * This callback is optional, if not implemented the bridge will be + * considered as always having a component attached to its output. + * Bridges that implement this callback shall set the + * DRM_BRIDGE_OP_DETECT flag in their &drm_bridge->ops. + * + * This is the atomic version of &drm_bridge_funcs.detect. + * + * To avoid races against concurrent connector state updates, the + * helper libraries always call this with ctx set to a valid context, + * and &drm_mode_config.connection_mutex will always be locked with + * the ctx parameter set to this ctx. This allows taking additional + * locks as required. + * + * RETURNS: + * + * &drm_connector_status indicating the bridge output status, + * or the error code returned by drm_modeset_lock(), -EDEADLK. + */ + int (*detect_ctx)(struct drm_bridge *bridge, + struct drm_connector *connector, + struct drm_modeset_acquire_ctx *ctx); + /** * @get_modes: * @@ -1527,6 +1554,9 @@ drm_atomic_helper_bridge_propagate_bus_fmt(struct drm_bridge *bridge, enum drm_connector_status drm_bridge_detect(struct drm_bridge *bridge, struct drm_connector *connector); +int drm_bridge_detect_ctx(struct drm_bridge *bridge, + struct drm_connector *connector, + struct drm_modeset_acquire_ctx *ctx); int drm_bridge_get_modes(struct drm_bridge *bridge, struct drm_connector *connector); const struct drm_edid *drm_bridge_edid_read(struct drm_bridge *bridge, -- 2.51.2
