i2c-piix4: Blacklist two mainboards

We had a report that running sensors-detect on a Sapphire AM2RD790
motherbord killed the CPU. While the exact cause is still unknown,
I'd rather play it safe and prevent any access to the SMBus on that
machine by not letting the i2c-piix4 driver attach to the SMBus host
device on that machine. Also blacklist a similar board made by DFI.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

drivers/i2c/busses/i2c-piix4.c

@@ -108,7 +108,27 @@ static int srvrworks_csb5_delay;
 static struct pci_driver piix4_driver;
 static struct i2c_adapter piix4_adapter;
 
-static struct dmi_system_id __devinitdata piix4_dmi_table[] = {
+static struct dmi_system_id __devinitdata piix4_dmi_blacklist[] = {
+	{
+		.ident = "Sapphire AM2RD790",
+		.matches = {
+			DMI_MATCH(DMI_BOARD_VENDOR, "SAPPHIRE Inc."),
+			DMI_MATCH(DMI_BOARD_NAME, "PC-AM2RD790"),
+		},
+	},
+	{
+		.ident = "DFI Lanparty UT 790FX",
+		.matches = {
+			DMI_MATCH(DMI_BOARD_VENDOR, "DFI Inc."),
+			DMI_MATCH(DMI_BOARD_NAME, "LP UT 790FX"),
+		},
+	},
+	{ }
+};
+
+/* The IBM entry is in a separate table because we only check it
+   on Intel-based systems */
+static struct dmi_system_id __devinitdata piix4_dmi_ibm[] = {
 	{
 		.ident = "IBM",
 		.matches = { DMI_MATCH(DMI_SYS_VENDOR, "IBM"), },
@@ -127,8 +147,16 @@ static int __devinit piix4_setup(struct pci_dev *PIIX4_dev,
 	    (PIIX4_dev->device == PCI_DEVICE_ID_SERVERWORKS_CSB5))
 		srvrworks_csb5_delay = 1;
 
+	/* On some motherboards, it was reported that accessing the SMBus
+	   caused severe hardware problems */
+	if (dmi_check_system(piix4_dmi_blacklist)) {
+		dev_err(&PIIX4_dev->dev,
+			"Accessing the SMBus on this system is unsafe!\n");
+		return -EPERM;
+	}
+
 	/* Don't access SMBus on IBM systems which get corrupted eeproms */
-	if (dmi_check_system(piix4_dmi_table) &&
+	if (dmi_check_system(piix4_dmi_ibm) &&
 			PIIX4_dev->vendor == PCI_VENDOR_ID_INTEL) {
 		dev_err(&PIIX4_dev->dev, "IBM system detected; this module "
 			"may corrupt your serial eeprom! Refusing to load "