diff --git a/scripts/setup.sh b/scripts/setup.sh
index c044eb685f..2fd520ac4d 100755
--- a/scripts/setup.sh
+++ b/scripts/setup.sh
@@ -63,8 +63,9 @@ function usage() {
 	echo "PCI_BLOCKED       Whitespace separated list of PCI devices (NVMe, I/OAT, VMD, Virtio)."
 	echo "                  Each device must be specified as a full PCI address."
 	echo "                  E.g. PCI_ALLOWED=\"0000:01:00.0 0000:02:00.0\""
-	echo "                  To block all PCI devices use a non-valid address."
-	echo "                  E.g. PCI_BLOCKED=\"none\""
+	echo "                  To block all PCI devices: PCI_ALLOWED=\"none\""
+	echo "                  To allow all PCI devices except 0000:01:00.0: PCI_BLOCKED=\"0000:01:00.0\""
+	echo "                  To allow only PCI device 0000:01:00.0: PCI_ALLOWED=\"0000:01:00.0\""
 	echo "                  If PCI_ALLOWED and PCI_BLOCKED are empty or unset, all PCI devices"
 	echo "                  will be bound."
 	echo "                  Each device in PCI_BLOCKED will be ignored (driver won't be changed)."