[PATCH v8 20/29] drm/bridge_connector: avoid detect-based HPD notifications for DisplayPort

[Yongxing Mou <yongxing.mou@oss.qualcomm.com>]

When MST is active, the SST connector reports disconnected even though
the physical DP link is still connected. drm_bridge_connector_detect()
forwards this result to the bridge chain as an HPD notification.

On MSM DP, this notification invokes unplug handling and tears down the
active link and MST topology while the cable is still plugged in.

For DisplayPort connectors with an HPD source, stop notifying the bridge
chain from the detect path. Plug, unplug and IRQ_HPD notifications remain
handled through the existing HPD event path.

Preserve detect-based notifications for other connector types and for
DisplayPort connectors without an HPD source.

Signed-off-by: Yongxing Mou <yongxing.mou@oss.qualcomm.com>
---
 drivers/gpu/drm/display/drm_bridge_connector.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/display/drm_bridge_connector.c b/drivers/gpu/drm/display/drm_bridge_connector.c
index 1d4502126bff..dbe874d26911 100644
--- a/drivers/gpu/drm/display/drm_bridge_connector.c
+++ b/drivers/gpu/drm/display/drm_bridge_connector.c
@@ -315,7 +315,10 @@ static int drm_bridge_connector_detect_ctx(struct drm_connector *connector,
 				return ret;
 		}
 
-		drm_bridge_connector_hpd_notify(connector, status, DRM_CONNECTOR_NO_EXTRA_STATUS);
+		if (connector->connector_type != DRM_MODE_CONNECTOR_DisplayPort ||
+		    !bridge_connector->bridge_hpd)
+			drm_bridge_connector_hpd_notify(connector, status,
+							DRM_CONNECTOR_NO_EXTRA_STATUS);
 	} else {
 		switch (connector->connector_type) {
 		case DRM_MODE_CONNECTOR_DPI:

-- 
2.43.0