diff --git a/sys/dev/iicbus/iicbus.c b/sys/dev/iicbus/iicbus.c
index e4b6f8d45e39..26912fc0a87b 100644
--- a/sys/dev/iicbus/iicbus.c
+++ b/sys/dev/iicbus/iicbus.c
@@ -250,7 +250,7 @@ iicbus_print_child(device_t bus, device_t dev)
 		break;
 
 	default:
-		panic("%s: unknown class!\n", __FUNCTION__);
+		panic("%s: unknown class!", __FUNCTION__);
 	}
 
 	return (retval);
diff --git a/sys/dev/iicbus/iiconf.c b/sys/dev/iicbus/iiconf.c
index 42d3a9621c08..52e92f74344d 100644
--- a/sys/dev/iicbus/iiconf.c
+++ b/sys/dev/iicbus/iiconf.c
@@ -104,8 +104,12 @@ iicbus_request_bus(device_t bus, device_t dev, int how)
 	int s, error = 0;
 
 	/* first, ask the underlying layers if the request is ok */
-	error = IICBUS_CALLBACK(device_get_parent(bus), IIC_REQUEST_BUS,
-				(caddr_t)&how);
+	do {
+		error = IICBUS_CALLBACK(device_get_parent(bus),
+						IIC_REQUEST_BUS, (caddr_t)&how);
+		if (error)
+			error = iicbus_poll(sc, how);
+	} while (error == EWOULDBLOCK);
 
 	while (!error) {
 		s = splhigh();	
diff --git a/sys/dev/smbus/smb.c b/sys/dev/smbus/smb.c
index 331e6b91e193..7bf1af68ea3a 100644
--- a/sys/dev/smbus/smb.c
+++ b/sys/dev/smbus/smb.c
@@ -171,7 +171,7 @@ smbwrite(dev_t dev, struct uio * uio, int ioflag)
 {
 	/* not supported */
 
-	return (ENODEV);
+	return (EINVAL);
 }
 
 static int
@@ -179,7 +179,7 @@ smbread(dev_t dev, struct uio * uio, int ioflag)
 {
 	/* not supported */
 
-	return (ENODEV);
+	return (EINVAL);
 }
 
 static int
diff --git a/sys/dev/smbus/smbconf.c b/sys/dev/smbus/smbconf.c
index d97305c1c553..1d44ef354202 100644
--- a/sys/dev/smbus/smbconf.c
+++ b/sys/dev/smbus/smbconf.c
@@ -132,8 +132,12 @@ smbus_request_bus(device_t bus, device_t dev, int how)
 	int s, error = 0;
 
 	/* first, ask the underlying layers if the request is ok */
-	error = SMBUS_CALLBACK(device_get_parent(bus), SMB_REQUEST_BUS,
-				(caddr_t)&how);
+	do {
+		error = SMBUS_CALLBACK(device_get_parent(bus),
+						SMB_REQUEST_BUS, (caddr_t)&how);
+		if (error)
+			error = smbus_poll(sc, how);
+	} while (error == EWOULDBLOCK);
 
 	while (!error) {
 		s = splhigh();