1 files changed, 28 insertions, 5 deletions

diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c
index 235fb7a5a8a5..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
@@ -268,7 +270,12 @@ static long list_size;
 
 static void domain_remove_dev_info(struct dmar_domain *domain);
 
-int dmar_disabled;
+#ifdef CONFIG_DMAR_DEFAULT_ON
+int dmar_disabled = 0;
+#else
+int dmar_disabled = 1;
+#endif /*CONFIG_DMAR_DEFAULT_ON*/
+
 static int __initdata dmar_map_gfx = 1;
 static int dmar_forcedac;
 static int intel_iommu_strict;
@@ -284,9 +291,12 @@ static int __init intel_iommu_setup(char *str)
         if (!str)
                 return -EINVAL;
         while (*str) {
-                if (!strncmp(str, "off", 3)) {
+                if (!strncmp(str, "on", 2)) {
+                        dmar_disabled = 0;
+                        printk(KERN_INFO "Intel-IOMMU: enabled\n");
+                } else if (!strncmp(str, "off", 3)) {
                         dmar_disabled = 1;
-                        printk(KERN_INFO"Intel-IOMMU: disabled\n");
+                        printk(KERN_INFO "Intel-IOMMU: disabled\n");
                 } else if (!strncmp(str, "igfx_off", 8)) {
                         dmar_map_gfx = 0;
                         printk(KERN_INFO
@@ -438,7 +448,8 @@ static struct intel_iommu *device_to_iommu(u8 bus, u8 devfn)
                         continue;
 
                 for (i = 0; i < drhd->devices_cnt; i++)
-                        if (drhd->devices[i]->bus->number == bus &&
+                        if (drhd->devices[i] &&
+                            drhd->devices[i]->bus->number == bus &&
                             drhd->devices[i]->devfn == devfn)
                                 return drhd->iommu;
 
@@ -776,7 +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;
 
@@ -3128,3 +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);