Limit the shortcut which unconditionally returns connected status when a next bridge exists. Only apply this logic if the last bridge in the chain is a panel and the bridges attached after Analogix DP bridge lack DRM_BRIDGE_OP_DETECT, which called 'force_connected_mode'. For all other cases, rely on analogix_dp_detect_hpd() to report accurate hotplug state.
Background for the special handling: - If the chain ends with a DP connector bridge, the connector relies on Analogix DP to perform detection. We must avoid hardcoding connected status here. - For intermediate bridges such as PS8625 / PTN3460 without detect support [1], historically the bridge connector defaults to connected via drm_helper_probe_detect() when no per-bridge detect callback exists. [1] https://lore.kernel.org/all/[email protected]/ Reported-by: Heiko Stuebner <[email protected]> Link: https://lore.kernel.org/all/5209243.oAaWjsssbx@diego/ Signed-off-by: Damon Ding <[email protected]> --- Changes in v3: - Add missing drm_bridge_put() after drm_bridge_chain_get_last_bridge() to fix a reference count leak.(Sashiko) - Report panel endpoints as always connected from analogix_dp_get_plug_in_status() via newly added &analogix_dp_device.force_connected_mode. --- .../drm/bridge/analogix/analogix_dp_core.c | 30 +++++++++++++++++-- .../drm/bridge/analogix/analogix_dp_core.h | 1 + .../gpu/drm/bridge/analogix/analogix_dp_reg.c | 3 ++ 3 files changed, 31 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c index 853b6a6a7fe4..df898f314254 100644 --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c @@ -912,15 +912,30 @@ analogix_dp_bridge_detect(struct drm_bridge *bridge, struct drm_connector *conne struct analogix_dp_device *dp = to_dp(bridge); enum drm_connector_status status = connector_status_disconnected; - if (dp->bridge.next_bridge) - return connector_status_connected; - if (!analogix_dp_detect_hpd(dp)) status = connector_status_connected; return status; } +static bool analogix_dp_bridge_force_connected(struct analogix_dp_device *dp) +{ + struct drm_bridge *last_bridge; + bool force_connected = false; + + drm_for_each_bridge_in_chain_from(dp->bridge.next_bridge, bridge) { + if (bridge->ops & DRM_BRIDGE_OP_DETECT) + return false; + } + + last_bridge = drm_bridge_chain_get_last_bridge(dp->encoder); + if (last_bridge) + force_connected = drm_bridge_is_panel(last_bridge); + drm_bridge_put(last_bridge); + + return force_connected; +} + static int analogix_dp_bridge_attach(struct drm_bridge *bridge, struct drm_encoder *encoder, enum drm_bridge_attach_flags flags) @@ -940,6 +955,15 @@ static int analogix_dp_bridge_attach(struct drm_bridge *bridge, dev_err(dp->dev, "failed to attach following panel or bridge (%d)\n", ret); return ret; } + + /* + * Only assume connected when the bridge chain ends with a panel. + * Panel bridges lack a detect callback and historically rely on + * this shortcut. For other next bridge types (e.g., DP connector + * bridges), fall back to analogix_dp_detect_hpd() to report + * accurate hotplug state. + */ + dp->force_connected_mode = analogix_dp_bridge_force_connected(dp); } return 0; diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h index 6a3566b2e8de..5f5698c73d88 100644 --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h @@ -170,6 +170,7 @@ struct analogix_dp_device { bool force_hpd; bool fast_train_enable; bool psr_supported; + bool force_connected_mode; u8 dpcd[DP_RECEIVER_CAP_SIZE]; diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c index af5e5a8ec88d..abbcdba1a438 100644 --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c @@ -533,6 +533,9 @@ int analogix_dp_get_plug_in_status(struct analogix_dp_device *dp) { u32 reg; + if (dp->force_connected_mode) + return 0; + if (dp->hpd_gpiod) { if (gpiod_get_value(dp->hpd_gpiod)) return 0; -- 2.34.1
