i2c-i801: Don't use the block buffer for I2C block writes

commit c074c39d62306efa5ba7c69c1a1531bc7333d252 upstream.

Experience has shown that the block buffer can only be used for SMBus
(not I2C) block transactions, even though the datasheet doesn't
mention this limitation.

Reported-by: Felix Rubinstein <felixru@gmail.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Oleg Ryjkov <oryjkov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
index dc7ea32b69a8f64c3a09725cd54748fb8c95b9c8..177346e093e2069f82f606189dc47a31770f3def 100644 (file)
--- a/drivers/i2c/busses/i2c-i801.c
+++ b/drivers/i2c/busses/i2c-i801.c
@@ -413,9 +413,11 @@ static int i801_block_transaction(union i2c_smbus_data *data, char read_write,
                data->block[0] = 32;    /* max for SMBus block reads */
        }
 
+       /* Experience has shown that the block buffer can only be used for
+          SMBus (not I2C) block transactions, even though the datasheet
+          doesn't mention this limitation. */
        if ((i801_features & FEATURE_BLOCK_BUFFER)
-        && !(command == I2C_SMBUS_I2C_BLOCK_DATA
-             && read_write == I2C_SMBUS_READ)
+        && command != I2C_SMBUS_I2C_BLOCK_DATA
         && i801_set_block_buffer_mode() == 0)
                result = i801_block_transaction_by_block(data, read_write,
                                                         hwpec);