path: root/Documentation/i2c
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authorJean Delvare <khali@linux-fr.org>2006-04-25 13:37:25 +0200
committerGreg Kroah-Hartman <gregkh@suse.de>2006-06-22 11:10:32 -0700
commitf9ba6c04ef1dcf16f7179b7883e9751baaac218e (patch)
tree0d66c8aab1ea1c0343744925e53f7e9111daaff0 /Documentation/i2c
parent7aadb8f943f6f8fb48962099cfba05ad0518b0ac (diff)
[PATCH] I2C: i2c-piix4: Document the IBM problem more clearly
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>
Diffstat (limited to 'Documentation/i2c')
1 files changed, 14 insertions, 0 deletions
diff --git a/Documentation/i2c/busses/i2c-piix4 b/Documentation/i2c/busses/i2c-piix4
index a706ae6a1b41..921476333235 100644
--- a/Documentation/i2c/busses/i2c-piix4
+++ b/Documentation/i2c/busses/i2c-piix4
@@ -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: