1 files changed, 14 insertions, 0 deletions

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index e872ac925b4b..832175d9ca25 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -35,6 +35,20 @@ static void __devinit quirk_mellanox_tavor(struct pci_dev *dev)
 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_MELLANOX,PCI_DEVICE_ID_MELLANOX_TAVOR,quirk_mellanox_tavor);
 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_MELLANOX,PCI_DEVICE_ID_MELLANOX_TAVOR_BRIDGE,quirk_mellanox_tavor);
 
+/* Many VIA bridges seem to corrupt data for DAC. Disable it here */
+int forbid_dac __read_mostly;
+EXPORT_SYMBOL(forbid_dac);
+
+static __devinit void via_no_dac(struct pci_dev *dev)
+{
+        if ((dev->class >> 8) == PCI_CLASS_BRIDGE_PCI && forbid_dac == 0) {
+                dev_info(&dev->dev,
+                        "VIA PCI bridge detected. Disabling DAC.\n");
+                forbid_dac = 1;
+        }
+}
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_VIA, PCI_ANY_ID, via_no_dac);
+
 /* Deal with broken BIOS'es that neglect to enable passive release,
    which can cause problems in combination with the 82441FX/PPro MTRRs */
 static void quirk_passive_release(struct pci_dev *dev)