diff --git a/southbridge/amd/cs5536/smbus_initram.c b/southbridge/amd/cs5536/smbus_initram.c
index e462c14b30..1ba2d72038 100644
--- a/southbridge/amd/cs5536/smbus_initram.c
+++ b/southbridge/amd/cs5536/smbus_initram.c
@@ -69,7 +69,7 @@ static void smbus_init(void)
  */
 static void smbus_delay(void)
 {
-	/* inb(0x80); */
+	/* udelay(1); */
 }
 
 /**
diff --git a/southbridge/nvidia/mcp55/mcp55_smbus.h b/southbridge/nvidia/mcp55/mcp55_smbus.h
index 714e44f51f..fa83bb0f96 100644
--- a/southbridge/nvidia/mcp55/mcp55_smbus.h
+++ b/southbridge/nvidia/mcp55/mcp55_smbus.h
@@ -39,8 +39,7 @@
 
 static inline void smbus_delay(void)
 {
-	/* let's hope this is not optimized out */
-	(void) inb(0x80);
+	udelay(1);
 }
 
 int do_smbus_recv_byte(u16 smbus_io_base, u8 device);