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H A Di2c-piix4.c88fa2dfb Tue Oct 10 11:11:15 CDT 2017 Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> i2c: piix4: Disable completely the IMC during SMBUS_BLOCK_DATA

SMBUS_BLOCK_DATA transactions might fail due to a race condition with
the IMC (Integrated Micro Controller), even when the IMC semaphore
is used.

This bug has been reported and confirmed by AMD, who suggested as a
solution an IMC firmware upgrade (obtained via BIOS update) and
disabling the IMC during SMBUS_BLOCK_DATA transactions.

Even without the IMC upgrade, the SMBUS is much more stable with this
patch.

Tested on a Bettong-alike board.

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
88fa2dfb Tue Oct 10 11:11:15 CDT 2017 Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> i2c: piix4: Disable completely the IMC during SMBUS_BLOCK_DATA

SMBUS_BLOCK_DATA transactions might fail due to a race condition with
the IMC (Integrated Micro Controller), even when the IMC semaphore
is used.

This bug has been reported and confirmed by AMD, who suggested as a
solution an IMC firmware upgrade (obtained via BIOS update) and
disabling the IMC during SMBUS_BLOCK_DATA transactions.

Even without the IMC upgrade, the SMBUS is much more stable with this
patch.

Tested on a Bettong-alike board.

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>