diff --git a/drivers/platform/x86/apple-gmux.c b/drivers/platform/x86/apple-gmux.c
index 587a603..1146fe5 100644
--- a/drivers/platform/x86/apple-gmux.c
+++ b/drivers/platform/x86/apple-gmux.c
@@ -142,8 +142,9 @@ static u8 gmux_index_read8(struct apple_gmux_data *gmux_data, int port)
 	u8 val;
 
 	mutex_lock(&gmux_data->index_lock);
-	outb((port & 0xff), gmux_data->iostart + GMUX_PORT_READ);
 	gmux_index_wait_ready(gmux_data);
+	outb((port & 0xff), gmux_data->iostart + GMUX_PORT_READ);
+	gmux_index_wait_complete(gmux_data);
 	val = inb(gmux_data->iostart + GMUX_PORT_VALUE);
 	mutex_unlock(&gmux_data->index_lock);
 
@@ -166,8 +167,9 @@ static u32 gmux_index_read32(struct apple_gmux_data *gmux_data, int port)
 	u32 val;
 
 	mutex_lock(&gmux_data->index_lock);
-	outb((port & 0xff), gmux_data->iostart + GMUX_PORT_READ);
 	gmux_index_wait_ready(gmux_data);
+	outb((port & 0xff), gmux_data->iostart + GMUX_PORT_READ);
+	gmux_index_wait_complete(gmux_data);
 	val = inl(gmux_data->iostart + GMUX_PORT_VALUE);
 	mutex_unlock(&gmux_data->index_lock);