drm/i915/hdcp: link hdcp2 recovery on link enc stopped

When stream encryption enabling fails due to Link encryption status
has stopped, prepare HDCP2 for recovery by disabling port authentication
and encryption such that it can re-attempt port authentication
and encryption.

Cc: Ramalingam C <ramalingam.c@intel.com>
Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Signed-off-by: Anshuman Gupta <anshuman.gupta@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210319100208.5886-3-anshuman.gupta@intel.com

drivers/gpu/drm/i915/display/intel_hdcp.c

@@ -1721,6 +1721,7 @@ static int hdcp2_enable_stream_encryption(struct intel_connector *connector)
 {
 	struct intel_digital_port *dig_port = intel_attached_dig_port(connector);
 	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct hdcp_port_data *data = &dig_port->hdcp_port_data;
 	struct intel_hdcp *hdcp = &connector->hdcp;
 	enum transcoder cpu_transcoder = hdcp->cpu_transcoder;
 	enum port port = dig_port->base.port;
@@ -1730,7 +1731,8 @@ static int hdcp2_enable_stream_encryption(struct intel_connector *connector)
 			    LINK_ENCRYPTION_STATUS)) {
 		drm_err(&dev_priv->drm, "[%s:%d] HDCP 2.2 Link is not encrypted\n",
 			connector->base.name, connector->base.base.id);
-		return -EPERM;
+		ret = -EPERM;
+		goto link_recover;
 	}
 
 	if (hdcp->shim->stream_2_2_encryption) {
@@ -1744,6 +1746,15 @@ static int hdcp2_enable_stream_encryption(struct intel_connector *connector)
 			    transcoder_name(hdcp->stream_transcoder));
 	}
 
+	return 0;
+
+link_recover:
+	if (hdcp2_deauthenticate_port(connector) < 0)
+		drm_dbg_kms(&dev_priv->drm, "Port deauth failed.\n");
+
+	dig_port->hdcp_auth_status = false;
+	data->k = 0;
+
 	return ret;
 }