From cb640b2ca54617f4a9d4d6efd5ff2afd6be11f19 Mon Sep 17 00:00:00 2001 From: Dmitry Baryshkov Date: Sat, 2 Aug 2025 13:40:35 +0300 Subject: [PATCH] drm/bridge: display-connector: don't set OP_DETECT for DisplayPorts Detecting the monitor for DisplayPort targets is more complicated than just reading the HPD pin level: it requires reading the DPCD in order to check what kind of device is attached to the port and whether there is an actual display attached. In order to let DRM framework handle such configurations, disable DRM_BRIDGE_OP_DETECT for dp-connector devices, letting the actual DP driver perform detection. This still keeps DRM_BRIDGE_OP_HPD enabled, so it is valid for the bridge to report HPD events. Currently inside the kernel there are only two targets which list hpd-gpios for dp-connector devices: arm64/qcom/qcs6490-rb3gen2 and arm64/qcom/sa8295p-adp. Both should be fine with this change. Cc: Bjorn Andersson Cc: Konrad Dybcio Cc: linux-arm-msm@vger.kernel.org Acked-by: Laurent Pinchart Link: https://lore.kernel.org/r/20250802-dp-conn-no-detect-v1-1-2748c2b946da@oss.qualcomm.com Signed-off-by: Dmitry Baryshkov --- drivers/gpu/drm/bridge/display-connector.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/bridge/display-connector.c b/drivers/gpu/drm/bridge/display-connector.c index d7e1c2f8f53ca..e9f16dbc95353 100644 --- a/drivers/gpu/drm/bridge/display-connector.c +++ b/drivers/gpu/drm/bridge/display-connector.c @@ -373,7 +373,8 @@ static int display_connector_probe(struct platform_device *pdev) if (conn->bridge.ddc) conn->bridge.ops |= DRM_BRIDGE_OP_EDID | DRM_BRIDGE_OP_DETECT; - if (conn->hpd_gpio) + /* Detecting the monitor requires reading DPCD */ + if (conn->hpd_gpio && type != DRM_MODE_CONNECTOR_DisplayPort) conn->bridge.ops |= DRM_BRIDGE_OP_DETECT; if (conn->hpd_irq >= 0) conn->bridge.ops |= DRM_BRIDGE_OP_HPD; -- 2.47.3