[PATCH] I2C: i2c-piix4: Remove the fix_hstcfg parameter

This patch removes the fix_hstcfg option from the driver and related
SMBus Interrupt Select register magic because now we know what are
valid values for this register. This patch updates the documentation
and adds new IRQ mode check so we are sure not to miss any new
"unusual" value.

The PCI quirk for users of fix_hstcfg was not developed because the
chipset lacks of subsystem ID registers and DMI is stated "To be
filled". Impact to existing systems is minimal because the problem
showed up on motherboards like 10 years back. On the other hand users
of newer Serverworks and HT1000 systems won't be misleaded by the
message suggesting to try the fix_hstcfg any more.

Signed-off-by: Rudolf Marek <r.marek@sh.cvut.cz>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/i2c/busses/i2c-piix4.c b/drivers/i2c/busses/i2c-piix4.c
index 5f06e81..05af7b0 100644
--- a/drivers/i2c/busses/i2c-piix4.c
+++ b/drivers/i2c/busses/i2c-piix4.c
@@ -102,13 +102,6 @@
 		 "Forcibly enable the PIIX4 at the given address. "
 		 "EXTREMELY DANGEROUS!");
 
-/* If fix_hstcfg is set to anything different from 0, we reset one of the
-   registers to be a valid value. */
-static int fix_hstcfg;
-module_param (fix_hstcfg, int, 0);
-MODULE_PARM_DESC(fix_hstcfg,
-		"Fix config register. Needed on some boards (Force CPCI735).");
-
 static int piix4_transaction(void);
 
 static unsigned short piix4_smba;
@@ -166,22 +159,6 @@
 
 	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) {
-		if (fix_hstcfg) {
-			dev_info(&PIIX4_dev->dev, "Working around buggy BIOS "
-					"(I2C)\n");
-			temp &= 0xfd;
-			pci_write_config_byte(PIIX4_dev, SMBHSTCFG, temp);
-		} else {
-			dev_info(&PIIX4_dev->dev, "Unusual config register "
-					"value\n");
-			dev_info(&PIIX4_dev->dev, "Try using fix_hstcfg=1 if "
-					"you experience problems\n");
-		}
-	}
- 
 	/* If force_addr is set, we program the new address here. Just to make
 	   sure, we disable the PIIX4 first. */
 	if (force_addr) {
@@ -214,7 +191,7 @@
 		}
 	}
 
-	if ((temp & 0x0E) == 8)
+	if (((temp & 0x0E) == 8) || ((temp & 0x0E) == 2))
 		dev_dbg(&PIIX4_dev->dev, "Using Interrupt 9 for SMBus.\n");
 	else if ((temp & 0x0E) == 0)
 		dev_dbg(&PIIX4_dev->dev, "Using Interrupt SMI# for SMBus.\n");