diff --git a/drivers/firmware/dcdbas.c b/drivers/firmware/dcdbas.c
index 69ad529d92fbb83d56694402710eebe1941391e8..ea5ac2dc1233748a7722fec6df4e5d3aa0b44f49 100644
--- a/drivers/firmware/dcdbas.c
+++ b/drivers/firmware/dcdbas.c
@@ -268,8 +268,10 @@ int dcdbas_smi_request(struct smi_cmd *smi_cmd)
 	}
 
 	/* generate SMI */
+	/* inb to force posted write through and make SMI happen now */
 	asm volatile (
-		"outb %b0,%w1"
+		"outb %b0,%w1\n"
+		"inb %w1"
 		: /* no output args */
 		: "a" (smi_cmd->command_code),
 		  "d" (smi_cmd->command_address),