6.1-stable review patch. If anyone has any objections, please let me know.
------------------
From: Dmitry Baryshkov dmitry.baryshkov@oss.qualcomm.com
[ 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 andersson@kernel.org Cc: Konrad Dybcio konradybcio@kernel.org Cc: linux-arm-msm@vger.kernel.org Acked-by: Laurent Pinchart laurent.pinchart+renesas@ideasonboard.com Link: https://lore.kernel.org/r/20250802-dp-conn-no-detect-v1-1-2748c2b946da@oss.q... Signed-off-by: Dmitry Baryshkov dmitry.baryshkov@oss.qualcomm.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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 9a12449ad7b87..8eded18ad2ec2 100644 --- a/drivers/gpu/drm/bridge/display-connector.c +++ b/drivers/gpu/drm/bridge/display-connector.c @@ -364,7 +364,8 @@ 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;