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-rw-r--r--drivers/pci/intel-iommu.c16
1 files changed, 15 insertions, 1 deletions
diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c
index f4b7c79023f..f3f686581a9 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);