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[PATCH] I2C: i2c-piix4: Document the IBM problem more clearly

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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.

Closes bug #6429.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Jean Delvare 2006-04-25 13:37:25 +02:00 committed by Greg Kroah-Hartman
parent 7aadb8f943
commit f9ba6c04ef
2 changed files with 15 additions and 1 deletions
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14
Documentation/i2c/busses/i2c-piix4
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@ -82,3 +82,17 @@ 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

2
drivers/i2c/busses/i2c-piix4.c
View file

@ -130,7 +130,7 @@ static int __devinit piix4_setup(struct pci_dev *PIIX4_dev,
/* Don't access SMBus on IBM systems which get corrupted eeproms */
if (dmi_check_system(piix4_dmi_table) &&
PIIX4_dev->vendor == PCI_VENDOR_ID_INTEL) {
dev_err(&PIIX4_dev->dev, "IBM Laptop detected; this module "
dev_err(&PIIX4_dev->dev, "IBM system detected; this module "
"may corrupt your serial eeprom! Refusing to load "
"module!\n");
return -EPERM;