From: Dmitry Baryshkov Date: Sat, 2 Aug 2025 10:40:35 +0000 (+0300) Subject: drm/bridge: display-connector: don't set OP_DETECT for DisplayPorts X-Git-Tag: v6.17.8~537 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=de68849113b988a54ee994263ebf736840c05129;p=thirdparty%2Fkernel%2Fstable.git drm/bridge: display-connector: don't set OP_DETECT for DisplayPorts [ Upstream commit cb640b2ca54617f4a9d4d6efd5ff2afd6be11f19 ] 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 Signed-off-by: Sasha Levin --- diff --git a/drivers/gpu/drm/bridge/display-connector.c b/drivers/gpu/drm/bridge/display-connector.c index 52b7b5889e6fe..4f0295efb8f68 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;