Force CPCI735 bug workaround (patch by Tom Rini).

git-svn-id: http://lm-sensors.org/svn/lm-sensors/trunk@1961 7894878c-1315-0410-8ee3-d5d059ff63e0

kernel/busses/i2c-piix4.c

@@ -179,6 +179,15 @@ static int piix4_setup(struct pci_dev *PIIX4_dev, const struct pci_device_id *id
 	}
 
 	pci_read_config_byte(PIIX4_dev, SMBHSTCFG, &temp);
+
+	/* Some BIOS will set up the chipset incorrectly and leave a register
+	   in an undefined state (causing I2C to act very strangely). */
+	if (temp & 0x02) {
+		printk("Worked around buggy BIOS (I2C)\n");
+		temp &= 0xfd;
+		pci_write_config_byte(PIIX4_dev, SMBHSTCFG, temp);
+	}
+
 /* If force_addr is set, we program the new address here. Just to make
    sure, we disable the PIIX4 first. */
 	if (force_addr) {