[PATCH] ASUS P4B SMBus quirks.

From Dominik Brodowski, comments says it all..

drivers/pci/quirks.c

@@ -646,6 +646,56 @@ static void __init quirk_eisa_bridge(struct pci_dev *dev)
 	dev->class = PCI_CLASS_BRIDGE_EISA << 8;
 }
 
+/*
+ * On ASUS P4B boards, the SMBus PCI Device within the ICH2/4 southbridge
+ * is not activated. The myth is that Asus said that they do not want the
+ * users to be irritated by just another PCI Device in the Win98 device
+ * manager. (see the file prog/hotplug/README.p4b in the lm_sensors 
+ * package 2.7.0 for details)
+ *
+ * The SMBus PCI Device can be activated by setting a bit in the ICH LPC 
+ * bridge. Unfortunately, this device has no subvendor/subdevice ID. So it 
+ * becomes necessary to do this tweak in two steps -- I've chosen the Host
+ * bridge as trigger.
+ */
+
+static int __initdata asus_hides_smbus = 0;
+
+static void __init asus_hides_smbus_hostbridge(struct pci_dev *dev)
+{
+	if (likely(dev->subsystem_vendor != PCI_VENDOR_ID_ASUSTEK))
+		return;
+
+	if ((dev->device == PCI_DEVICE_ID_INTEL_82845_HB) && 
+	    (dev->subsystem_device == 0x8088)) /* P4B533 */
+		asus_hides_smbus = 1;
+	if ((dev->device == PCI_DEVICE_ID_INTEL_82845G_HB) &&
+	    (dev->subsystem_device == 0x80b2)) /* P4PE */
+		asus_hides_smbus = 1;
+	if ((dev->device == PCI_DEVICE_ID_INTEL_82850_HB) &&
+	    (dev->subsystem_device == 0x8030)) /* P4T533 */
+		asus_hides_smbus = 1;
+	return;
+}
+
+static void __init asus_hides_smbus_lpc(struct pci_dev *dev)
+{
+	u16 val;
+	
+	if (likely(!asus_hides_smbus))
+		return;
+
+	pci_read_config_word(dev, 0xF2, &val);
+	if (val & 0x8) {
+		pci_write_config_word(dev, 0xF2, val & (~0x8));
+		pci_read_config_word(dev, 0xF2, &val);
+		if(val & 0x8)
+			printk(KERN_INFO "PCI: i801 SMBus device continues to play 'hide and seek'! 0x%x\n", val);
+		else
+			printk(KERN_INFO "PCI: Enabled i801 SMBus device\n");
+	}
+}
+
 /*
  *  The main table of quirks.
  */
@@ -725,6 +775,15 @@ static struct pci_fixup pci_fixups[] __devinitdata = {
 	
 	{ PCI_FIXUP_HEADER,	PCI_VENDOR_ID_INTEL,	PCI_DEVICE_ID_INTEL_82375,	quirk_eisa_bridge },
 
+	/*
+	 * on Asus P4B boards, the i801SMBus device is disabled at startup.
+	 */
+	{ PCI_FIXUP_HEADER,	PCI_VENDOR_ID_INTEL,	PCI_DEVICE_ID_INTEL_82845_HB,	asus_hides_smbus_hostbridge },
+	{ PCI_FIXUP_HEADER,	PCI_VENDOR_ID_INTEL,	PCI_DEVICE_ID_INTEL_82845G_HB,	asus_hides_smbus_hostbridge },
+	{ PCI_FIXUP_HEADER,	PCI_VENDOR_ID_INTEL,	PCI_DEVICE_ID_INTEL_82850_HB,	asus_hides_smbus_hostbridge },
+	{ PCI_FIXUP_HEADER,	PCI_VENDOR_ID_INTEL,	PCI_DEVICE_ID_INTEL_82801DB_0,	asus_hides_smbus_lpc },
+	{ PCI_FIXUP_HEADER,	PCI_VENDOR_ID_INTEL,	PCI_DEVICE_ID_INTEL_82801BA_0,	asus_hides_smbus_lpc },
+
 	{ 0 }
 };