diff --git a/drivers/misc/cardreader/alcor_pci.c b/drivers/misc/cardreader/alcor_pci.c
index cd402c89189ea..0a62307f7ffb9 100644
--- a/drivers/misc/cardreader/alcor_pci.c
+++ b/drivers/misc/cardreader/alcor_pci.c
@@ -139,7 +139,13 @@ static void alcor_pci_init_check_aspm(struct alcor_pci_priv *priv)
 	u32 val32;
 
 	priv->pdev_cap_off    = alcor_pci_find_cap_offset(priv, priv->pdev);
-	priv->parent_cap_off = alcor_pci_find_cap_offset(priv,
+	/*
+	 * A device might be attached to root complex directly and
+	 * priv->parent_pdev will be NULL. In this case we don't check its
+	 * capability and disable ASPM completely.
+	 */
+	if (!priv->parent_pdev)
+		priv->parent_cap_off = alcor_pci_find_cap_offset(priv,
 							 priv->parent_pdev);
 
 	if ((priv->pdev_cap_off == 0) || (priv->parent_cap_off == 0)) {