Properly document on which systems the i2c-piix4 SMBus driver will

refuse to load. Hopefully this will make it clearer for users, which
were often wondering why their destop or server systems were detected
as laptops.


git-svn-id: http://lm-sensors.org/svn/lm-sensors/trunk@4053 7894878c-1315-0410-8ee3-d5d059ff63e0

CHANGES

@@ -2,6 +2,7 @@ lm_sensors CHANGES file
 -----------------------
 
 2.10.1 (2006????)
+  File doc/busses/i2c-piix4: Update (2.6 backport)
   File etc/sensors.conf.eg: Add an smsc47m192 section
   Library: Fix device scan when no i2c support is present
            Add support for W83627EHF voltage inputs and alarms

doc/busses/i2c-piix4

@@ -85,3 +85,17 @@ the SMI mode.
 
 Please note that you don't need to do that in all cases, just when the SMBus is
 not working properly.
+
+
+Hardware-specific issues
+------------------------
+
+This driver will refuse to load on IBM systems with an Intel PIIX4 SMBus.
+Some of these machines have an RFID EEPROM (24RF08) connected to the SMBus,
+which can easily get corrupted due to a state machine bug. These are mostly
+Thinkpad laptops, but desktop systems may also be affected. We have no list
+of all affected systems, so the only safe solution was to prevent access to
+the SMBus on all IBM systems (detected using DMI data.)
+
+For additional information, read:
+http://www2.lm-sensors.nu/~lm78/cvs/lm_sensors2/README.thinkpad

kernel/busses/i2c-piix4.c

@@ -137,7 +137,7 @@ static int __devinit piix4_setup(struct pci_dev *PIIX4_dev,
 
 #ifdef CONFIG_X86
 	if(ibm_dmi_probe() && PIIX4_dev->vendor == PCI_VENDOR_ID_INTEL) {
-		printk(KERN_ERR "i2c-piix4.o: IBM Laptop detected; this module "
+		printk(KERN_ERR "i2c-piix4.o: IBM system detected; this module "
 			"may corrupt your serial eeprom! Refusing to load "
 			"module!\n");
 		return -EPERM;