drm/i915: Start repeater auth on READY/CP_IRQ

Second stage of HDCP authentication starts at CP_IRQ or at the
assertion of READY bit from Repeater.

Till then repeater will be authenticating with its downstream devices.
So authenticated device count, depth and ksv_list readable from
repeaters are valid only after assertion of READY/CP_IRQ.

This patch makes sure that READY is polled before reading any
topology information.

Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/1516254488-4971-4-git-send-email-ramalingam.c@intel.com

drivers/gpu/drm/i915/intel_hdcp.c

@@ -150,6 +150,12 @@ int intel_hdcp_auth_downstream(struct intel_digital_port *intel_dig_port,
 
 	dev_priv = intel_dig_port->base.base.dev->dev_private;
 
+	ret = intel_hdcp_poll_ksv_fifo(intel_dig_port, shim);
+	if (ret) {
+		DRM_ERROR("KSV list failed to become ready (%d)\n", ret);
+		return ret;
+	}
+
 	ret = shim->read_bstatus(intel_dig_port, bstatus);
 	if (ret)
 		return ret;
@@ -161,12 +167,6 @@ int intel_hdcp_auth_downstream(struct intel_digital_port *intel_dig_port,
 		return 0;
 	}
 
-	ret = intel_hdcp_poll_ksv_fifo(intel_dig_port, shim);
-	if (ret) {
-		DRM_ERROR("KSV list failed to become ready (%d)\n", ret);
-		return ret;
-	}
-
 	ksv_fifo = kzalloc(num_downstream * DRM_HDCP_KSV_LEN, GFP_KERNEL);
 	if (!ksv_fifo)
 		return -ENOMEM;