From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B2545EB3649 for ; Tue, 3 Mar 2026 01:38:29 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 0087910E606; Tue, 3 Mar 2026 01:38:27 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=collabora.com header.i=@collabora.com header.b="QHjh5GCF"; dkim-atps=neutral Received: from bali.collaboradmins.com (bali.collaboradmins.com [148.251.105.195]) by gabe.freedesktop.org (Postfix) with ESMTPS id 093E810E08C for ; Tue, 3 Mar 2026 01:38:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1772501904; bh=NX8PprlBauLw/tHNs9H9iHjyPLMjnL119UcQNvumShw=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=QHjh5GCFc/EqyXMzPkB2FIflD/cEeWCgtj6d+kQjsFtuqOBGpsjsInXPtsYN7oZym TsbqCZPuuDiKipmqyupzj2TwNrZuZHKpX0x54se708RVn+agmF1PQ5+VK86Co9BSBr eMnGk0BvBGpMotBx064/EpEBGJtPYAzqld9ayHVyKUuOaZK9fK+q7MASET4zMLvIh8 FmDF1rOOdMH0m+Tgci8QlBDGlNM9R6cnCnVXH9We3EhJ24+OTZ/oxGlneCoePfCrOI mzI6zfMHNAfBUt1Qo9+DSMYsilmgj01LALAqU69vFdiT3DiwQePpmxogqmBGyXrzpo 2zFVc8kK+sW4w== Received: from localhost (unknown [86.123.23.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (prime256v1) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: cristicc) by bali.collaboradmins.com (Postfix) with ESMTPSA id 884D117E0EA3; Tue, 3 Mar 2026 02:38:24 +0100 (CET) From: Cristian Ciocaltea Date: Tue, 03 Mar 2026 03:38:07 +0200 Subject: [PATCH v4 1/4] drm/bridge: Add ->detect_ctx hook and drm_bridge_detect_ctx() MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260303-dw-hdmi-qp-scramb-v4-1-317d3b8bd219@collabora.com> References: <20260303-dw-hdmi-qp-scramb-v4-0-317d3b8bd219@collabora.com> In-Reply-To: <20260303-dw-hdmi-qp-scramb-v4-0-317d3b8bd219@collabora.com> To: Andrzej Hajda , Neil Armstrong , Robert Foss , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Sandy Huang , =?utf-8?q?Heiko_St=C3=BCbner?= , Andy Yan Cc: kernel@collabora.com, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org, Diederik de Haas , Maud Spierings X-Mailer: b4 0.14.3 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" 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. Tested-by: Diederik de Haas Tested-by: Maud Spierings Signed-off-by: Cristian Ciocaltea --- 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 f8b0333a0a3b..1247573c2100 100644 --- a/drivers/gpu/drm/drm_bridge.c +++ b/drivers/gpu/drm/drm_bridge.c @@ -1345,6 +1345,64 @@ 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 4f19f7064ee3..31ef1496fe63 100644 --- a/include/drm/drm_bridge.h +++ b/include/drm/drm_bridge.h @@ -547,6 +547,33 @@ 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: * @@ -1542,6 +1569,9 @@ 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, -- 2.52.0