drm/radeon: Delay Connector detecting when HPD singals is unstable

[ Upstream commit 949658c ]

In some causes, HPD signals will jitter when plugging in
or unplugging HDMI.

Rescheduling the hotplug work for a second when EDID may still be
readable but HDP is disconnected, and fixes this issue.

Signed-off-by: Shixiong Ou <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>
Stable-dep-of: 979bfe2 ("Revert "drm/radeon: Delay Connector detecting when HPD singals is unstable"")
Signed-off-by: Sasha Levin <[email protected]>

Author: Shixiong Ou

drivers/gpu/drm/radeon/radeon_connectors.c

@@ -1267,6 +1267,16 @@ radeon_dvi_detect(struct drm_connector *connector, bool force)
 			goto exit;
 		}
 	}
+
+	if (dret && radeon_connector->hpd.hpd != RADEON_HPD_NONE &&
+	    !radeon_hpd_sense(rdev, radeon_connector->hpd.hpd) &&
+	    connector->connector_type == DRM_MODE_CONNECTOR_HDMIA) {
+		DRM_DEBUG_KMS("EDID is readable when HPD disconnected\n");
+		schedule_delayed_work(&rdev->hotplug_work, msecs_to_jiffies(1000));
+		ret = connector_status_disconnected;
+		goto exit;
+	}
+
 	if (dret) {
 		radeon_connector->detected_by_load = false;
 		radeon_connector_free_edid(connector);