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 0CA25FF885C for ; Sun, 26 Apr 2026 00:20:37 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id ABDE110E4D7; Sun, 26 Apr 2026 00:20:34 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=collabora.com header.i=@collabora.com header.b="aIwmUvhZ"; dkim-atps=neutral Received: from bali.collaboradmins.com (bali.collaboradmins.com [148.251.105.195]) by gabe.freedesktop.org (Postfix) with ESMTPS id AD54610E4D2 for ; Sun, 26 Apr 2026 00:20:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1777162828; bh=PhCBUZ9LP1QlSA5Vw3scKGIP9YUqVnd7mb1z6jP2Cgg=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=aIwmUvhZYNxAN75eBf2UNQliuzeBxHsJEEbVb1RCVGgUbMO9qeL5XU9gid7Qrzye8 vZkHT8VBBeas2OJ0FZF5CXqEHikha37LCjau4Uc8gcgM/lzXbak/Dj5RcMYSyGhxrw /FRaR/J1Tz1PWz7ey2u+rR1LErU2N7UXhaDzJsAMQDAuVnx0eH2lnggmtMYAWrxoEs F2vN8moPy3BQJCfofzBJyJ0kPN4vb5gkQUDB8RXZC1gCoRLUTbjbF/6uS/TyPbTvJ3 gGv9a+cs3ensFHMv7bt5+2UDsBHPF2dbZzL+X9i6tIlbMZINdi0aoxaRSvEWvTHti/ JG2M/y0yUJqiQ== Received: from localhost (unknown [100.64.0.241]) (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 B7BAB17E107E; Sun, 26 Apr 2026 02:20:28 +0200 (CEST) From: Cristian Ciocaltea Date: Sun, 26 Apr 2026 03:20:14 +0300 Subject: [PATCH v5 02/10] drm/bridge: Add detect_ctx hook and drm_bridge_detect_ctx() helper MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260426-dw-hdmi-qp-scramb-v5-2-d778e70c317b@collabora.com> References: <20260426-dw-hdmi-qp-scramb-v5-0-d778e70c317b@collabora.com> In-Reply-To: <20260426-dw-hdmi-qp-scramb-v5-0-d778e70c317b@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 0.15.1 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-aware .detect_ctx() callback to drm_bridge_funcs and a drm_bridge_detect_ctx() helper that accepts an optional drm_modeset_acquire_ctx. This enables bridge drivers to perform operations requiring modeset locking during connector detection, such as SCDC management for HDMI 2.0. When both ->detect_ctx and ->detect are defined, the former takes precedence. When ctx is NULL, locking is managed internally with EDEADLK retry. Tested-by: Diederik de Haas Tested-by: Maud Spierings Signed-off-by: Cristian Ciocaltea --- drivers/gpu/drm/drm_bridge.c | 66 ++++++++++++++++++++++++++++++++++++++++---- include/drm/drm_bridge.h | 43 +++++++++++++++++++++++++---- 2 files changed, 98 insertions(+), 11 deletions(-) diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c index 986e4c79a4e0..a5c6c2ea4ba6 100644 --- a/drivers/gpu/drm/drm_bridge.c +++ b/drivers/gpu/drm/drm_bridge.c @@ -1361,9 +1361,9 @@ EXPORT_SYMBOL(drm_atomic_bridge_chain_check); * @connector: attached connector * * If the bridge supports output detection, as reported by the - * DRM_BRIDGE_OP_DETECT bridge ops flag, call &drm_bridge_funcs.detect for the - * bridge and return the connection status. Otherwise return - * connector_status_unknown. + * 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. * * RETURNS: * The detection status on success, or connector_status_unknown if the bridge @@ -1372,12 +1372,68 @@ EXPORT_SYMBOL(drm_atomic_bridge_chain_check); enum drm_connector_status drm_bridge_detect(struct drm_bridge *bridge, struct drm_connector *connector) { + return drm_bridge_detect_ctx(bridge, connector, NULL); +} +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. + * + * 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) +{ + struct drm_modeset_acquire_ctx br_ctx; + int ret; + if (!(bridge->ops & DRM_BRIDGE_OP_DETECT)) return connector_status_unknown; - return bridge->funcs->detect(bridge, connector); + if (!bridge->funcs->detect_ctx) + return bridge->funcs->detect(bridge, connector); + + if (ctx) { + ret = bridge->funcs->detect_ctx(bridge, connector, ctx); + if (ret == -EDEADLK) + return ret; + + goto out; + } + + 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; + } + + drm_modeset_drop_locks(&br_ctx); + drm_modeset_acquire_fini(&br_ctx); +out: + if (WARN_ON(ret < 0)) + ret = connector_status_unknown; + + return ret; } -EXPORT_SYMBOL_GPL(drm_bridge_detect); +EXPORT_SYMBOL_GPL(drm_bridge_detect_ctx); /** * drm_bridge_get_modes - fill all modes currently valid for the sink into the diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h index d6cd0f5af045..6c751b96c3c9 100644 --- a/include/drm/drm_bridge.h +++ b/include/drm/drm_bridge.h @@ -535,10 +535,12 @@ struct drm_bridge_funcs { * * 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 non-atomic version of detect_ctx() callback, and is + * optional. If both are implemented, it is ignored. If none is + * 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. * * RETURNS: * @@ -547,6 +549,32 @@ 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 is the atomic version of detect() callback, and is optional. + * If both are implemented, it takes precedence. If none is 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. + * + * 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: * @@ -1002,8 +1030,8 @@ struct drm_bridge_timings { enum drm_bridge_ops { /** * @DRM_BRIDGE_OP_DETECT: The bridge can detect displays connected to - * its output. Bridges that set this flag shall implement the - * &drm_bridge_funcs->detect callback. + * its output. Bridges that set this flag shall implement either the + * &drm_bridge_funcs->detect or &drm_bridge_funcs->detect_ctx callbacks. */ DRM_BRIDGE_OP_DETECT = BIT(0), /** @@ -1565,6 +1593,9 @@ 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, -- 2.53.0