1 files changed, 15 insertions, 1 deletions

diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c
index f4b7c79023ff..f3f686581a90 100644
--- a/drivers/pci/intel-iommu.c
+++ b/drivers/pci/intel-iommu.c
@@ -61,6 +61,8 @@
 /* global iommu list, set NULL for ignored DMAR units */
 static struct intel_iommu **g_iommus;
 
+static int rwbf_quirk;
+
 /*
  * 0: Present
  * 1-11: Reserved
@@ -785,7 +787,7 @@ static void iommu_flush_write_buffer(struct intel_iommu *iommu)
         u32 val;
         unsigned long flag;
 
-        if (!cap_rwbf(iommu->cap))
+        if (!rwbf_quirk && !cap_rwbf(iommu->cap))
                 return;
         val = iommu->gcmd | DMA_GCMD_WBF;
 
@@ -3137,3 +3139,15 @@ static struct iommu_ops intel_iommu_ops = {
         .unmap          = intel_iommu_unmap_range,
         .iova_to_phys   = intel_iommu_iova_to_phys,
 };
+
+static void __devinit quirk_iommu_rwbf(struct pci_dev *dev)
+{
+        /*
+         * Mobile 4 Series Chipset neglects to set RWBF capability,
+         * but needs it:
+         */
+        printk(KERN_INFO "DMAR: Forcing write-buffer flush capability\n");
+        rwbf_quirk = 1;
+}
+
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x2a40, quirk_iommu_rwbf);