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. 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. Maintain compatibility by keeping the shortcut exclusively for panel endpoints. [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]> --- .../gpu/drm/bridge/analogix/analogix_dp_core.c | 16 ++++++++++++++-- .../gpu/drm/bridge/analogix/analogix_dp_core.h | 1 + 2 files changed, 15 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c index f05db455b430..a5a50b9ab8a7 100644 --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c @@ -906,8 +906,15 @@ 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->plat_data->next_bridge) - return connector_status_connected; + /* + * 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 through to analogix_dp_detect_hpd() to report + * accurate hotplug state. + */ + if (dp->plat_data->next_bridge && dp->last_bridge_is_panel) + status = connector_status_connected; if (!analogix_dp_detect_hpd(dp)) status = connector_status_connected; @@ -920,6 +927,7 @@ static int analogix_dp_bridge_attach(struct drm_bridge *bridge, enum drm_bridge_attach_flags flags) { struct analogix_dp_device *dp = to_dp(bridge); + struct drm_bridge *last_bridge; int ret = 0; if (!(flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR)) { @@ -934,6 +942,10 @@ 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; } + + last_bridge = drm_bridge_chain_get_last_bridge(dp->encoder); + if (drm_bridge_is_panel(last_bridge)) + dp->last_bridge_is_panel = true; } 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 2066e575ce10..bcb5674801a2 100644 --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h @@ -168,6 +168,7 @@ struct analogix_dp_device { bool force_hpd; bool fast_train_enable; bool psr_supported; + bool last_bridge_is_panel; u8 dpcd[DP_RECEIVER_CAP_SIZE]; -- 2.34.1
