--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -1389,6 +1389,24 @@ DECLARE_PCI_FIXUP_RESUME_EARLY(PCI_VENDOR_ID_SI, PCI_DEVICE_ID_SI_962,           quirk_si
 DECLARE_PCI_FIXUP_RESUME_EARLY(PCI_VENDOR_ID_SI,       PCI_DEVICE_ID_SI_963,           quirk_sis_96x_smbus);
 DECLARE_PCI_FIXUP_RESUME_EARLY(PCI_VENDOR_ID_SI,       PCI_DEVICE_ID_SI_LPC,           quirk_sis_96x_smbus);

+
+/*
+ * SiS 964 south bridge: BIOS typically hides SMBus device...
+ */
+static void quirk_sis_964_smbus(struct pci_dev *dev)
+{
+       u8 val = 0;
+       pci_read_config_byte(dev, 0x76, &val);
+       if (!(val & 0x01)) {
+               dev_info(&dev->dev, "Enabling SiS 964 SMBus\n");
+               pci_write_config_byte(dev, 0x76, val | 0x01);
+       }
+}
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_SI,     PCI_DEVICE_ID_SI_964,
+                                                       quirk_sis_964_smbus);
+DECLARE_PCI_FIXUP_RESUME_EARLY(PCI_VENDOR_ID_SI,       PCI_DEVICE_ID_SI_964,
+                                                       quirk_sis_964_smbus);


Still, I'm not quite sure if it is needed.