diff --git a/man2/iopl.2 b/man2/iopl.2
index a34ef793d..b12ec2aad 100644
--- a/man2/iopl.2
+++ b/man2/iopl.2
@@ -82,7 +82,8 @@ The calling process has insufficient privilege to call
 .BR iopl ();
 the
 .B CAP_SYS_RAWIO
-capability is required.
+capability is required to raise the I/O privilege level
+above its current value.
 .SH CONFORMING TO
 .BR iopl ()
 is Linux-specific and should not be used in programs that are