| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-Id: <20251203-dw-hdmi-qp-scramb-v1-1-836fe7401a69@collabora.com>
Date: Wed, 03 Dec 2025 20:27:52 +0200
From: Cristian Ciocaltea <cristian.ciocaltea@...labora.com>
To: Andrzej Hajda <andrzej.hajda@...el.com>,
Neil Armstrong <neil.armstrong@...aro.org>, Robert Foss <rfoss@...nel.org>,
Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
Jonas Karlman <jonas@...boo.se>, Jernej Skrabec <jernej.skrabec@...il.com>,
Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>,
David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
Sandy Huang <hjc@...k-chips.com>,
Heiko Stübner <heiko@...ech.de>,
Andy Yan <andy.yan@...k-chips.com>
Cc: kernel@...labora.com, dri-devel@...ts.freedesktop.org,
linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
linux-rockchip@...ts.infradead.org
Subject: [PATCH 1/4] drm/bridge: Add ->detect_ctx hook and
drm_bridge_detect_ctx()
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 <cristian.ciocaltea@...labora.com>
---
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
Powered by blists - more mailing lists