diff --git a/multipath/multipath.conf.5 b/multipath/multipath.conf.5
index 6095457..a568609 100644
--- a/multipath/multipath.conf.5
+++ b/multipath/multipath.conf.5
@@ -634,8 +634,13 @@ The default is: \fBno\fR
 .
 .TP
 .B checker_timeout
-Specify the timeout to use for path checkers and prioritizers that issue SCSI
-commands with an explicit timeout, in seconds.
+Specify the timeout to use for path checkers and prioritizers, in seconds.
+Only prioritizers that issue scsi commands use checker_timeout. Checkers
+that support an asynchronous mode (\fItur\fR and \fIdirectio\fR), will
+return shortly after being called by multipathd, regardless of whether the
+storage array responds. If the storage array hasn't responded, mulitpathd will
+check for a response every second, until \fIchecker_timeout\fR seconds have
+elapsed.
 .RS
 .TP
 The default is: in \fB/sys/block/sd<x>/device/timeout\fR