diff --git a/sys/dev/pci/pci_pci.c b/sys/dev/pci/pci_pci.c
index 6d058c41ac10..a378a078560b 100644
--- a/sys/dev/pci/pci_pci.c
+++ b/sys/dev/pci/pci_pci.c
@@ -683,6 +683,13 @@ pcib_attach_common(device_t dev)
      *     would be more widely routed than absolutely necessary.  We could
      *     then do a walk of the tree later and fix it.
      */
+
+    /*
+     * Always enable busmastering on bridges so that transactions
+     * initiated on the secondary bus are passed through to the
+     * primary bus.
+     */
+    pci_enable_busmaster(dev);
 }
 
 int