diff --git a/Documentation/s390/CommonIO b/Documentation/s390/CommonIO
index 59d1166..d684a6a 100644
--- a/Documentation/s390/CommonIO
+++ b/Documentation/s390/CommonIO
@@ -66,7 +66,7 @@
 
   When a device is un-ignored, device recognition and sensing is performed and 
   the device driver will be notified if possible, so the device will become
-  available to the system.
+  available to the system. Note that un-ignoring is performed asynchronously.
 
   You can also add ranges of devices to be ignored by piping to 
   /proc/cio_ignore; "add <device range>, <device range>, ..." will ignore the