1 files changed, 4 insertions, 1 deletions

diff --git a/drivers/pci/dmar.c b/drivers/pci/dmar.c
index e01ca4d6b3e6..0e98f6b6f515 100644
--- a/drivers/pci/dmar.c
+++ b/drivers/pci/dmar.c
@@ -614,8 +614,11 @@ void __init detect_intel_iommu(void)
 #endif
 #ifdef CONFIG_DMAR
                 if (ret && !no_iommu && !iommu_detected && !swiotlb &&
-                    !dmar_disabled)
+                    !dmar_disabled) {
                         iommu_detected = 1;
+                        /* Make sure ACS will be enabled */
+                        pci_request_acs();
+                }
 #endif
         }
         early_acpi_os_unmap_memory(dmar_tbl, dmar_tbl_size);