Disable Tom Tini's workaround by default. It can be re-enabled

by using the (new) fix_hstcfg parameter.


git-svn-id: http://lm-sensors.org/svn/lm-sensors/trunk@2083 7894878c-1315-0410-8ee3-d5d059ff63e0

doc/busses/i2c-piix4

@@ -7,7 +7,7 @@ Supported adapters:
   * Intel 82371AB PIIX4 and PIIX4E
   * Intel 82443MX (440MX)
     Datasheet: Publicly available at the Intel website
-  * ServerWorks OSB4 and CSB5 southbridges
+  * ServerWorks OSB4, CSB5  and CSB6 southbridges
     Datasheet: Only available via NDA from ServerWorks
   * Standard Microsystems (SMSC) SLC90E66 (Victory66) southbridge
     Datasheet: Publicly available at the SMSC website http://www.smsc.com
@@ -23,6 +23,8 @@ Module Parameters
   Forcibly enable the PIIX4. DANGEROUS!
 * force_addr: int
   Forcibly enable the PIIX4 at the given address. EXTREMELY DANGEROUS!
+* fix_hstcfg: int
+  Fix config register. Needed on some boards (Force CPCI735).
 
 
 Description
@@ -66,3 +68,8 @@ driver on those mainboards.
 
 The ServerWorks Southbridges, the Intel 440MX,
 and the Victory766 are identical to the PIIX4 in I2C/SMBus support.
+
+A few OSB4 southbridges are known to be misconfigured by the BIOS. In this
+case, you have you use the fix_hstcfg module parameter. Do not use it
+unless you know you have to, because in some cases it also breaks
+configuration on southbridges that don't need it.

kernel/busses/i2c-piix4.c

@@ -100,6 +100,11 @@ MODULE_PARM_DESC(force_addr,
 		 "Forcibly enable the PIIX4 at the given address. "
 		 "EXTREMELY DANGEROUS!");
 
+static int fix_hstcfg = 0;
+MODULE_PARM(fix_hstcfg, "i");
+MODULE_PARM_DESC(fix_hstcfg,
+		 "Fix config register. Needed on some boards (Force CPCI735).");
+
 static int piix4_transaction(void);
 
 
@@ -182,7 +187,7 @@ static int piix4_setup(struct pci_dev *PIIX4_dev, const struct pci_device_id *id
 
 	/* 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) {
+	if (fix_hstcfg && (temp & 0x02)) {
 		printk("Worked around buggy BIOS (I2C)\n");
 		temp &= 0xfd;
 		pci_write_config_byte(PIIX4_dev, SMBHSTCFG, temp);