5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jean Delvare <jdelvare@xxxxxxx> [ Upstream commit c1c9d0f6f7f1dbf29db996bd8e166242843a5f21 ] According to the Intel datasheets, software must reset the block buffer index twice for block process call transactions: once before writing the outgoing data to the buffer, and once again before reading the incoming data from the buffer. The driver is currently missing the second reset, causing the wrong portion of the block buffer to be read. Signed-off-by: Jean Delvare <jdelvare@xxxxxxx> Reported-by: Piotr Zakowski <piotr.zakowski@xxxxxxxxx> Closes: https://lore.kernel.org/linux-i2c/20240213120553.7b0ab120@endymion.delvare/ Fixes: 315cd67c9453 ("i2c: i801: Add Block Write-Block Read Process Call support") Reviewed-by: Alexander Sverdlin <alexander.sverdlin@xxxxxxxxx> Signed-off-by: Andi Shyti <andi.shyti@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/i2c/busses/i2c-i801.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c index 8ecba1ca9236..87c2c7c84736 100644 --- a/drivers/i2c/busses/i2c-i801.c +++ b/drivers/i2c/busses/i2c-i801.c @@ -522,11 +522,10 @@ static int i801_block_transaction_by_block(struct i801_priv *priv, /* Set block buffer mode */ outb_p(inb_p(SMBAUXCTL(priv)) | SMBAUXCTL_E32B, SMBAUXCTL(priv)); - inb_p(SMBHSTCNT(priv)); /* reset the data buffer index */ - if (read_write == I2C_SMBUS_WRITE) { len = data->block[0]; outb_p(len, SMBHSTDAT0(priv)); + inb_p(SMBHSTCNT(priv)); /* reset the data buffer index */ for (i = 0; i < len; i++) outb_p(data->block[i+1], SMBBLKDAT(priv)); } @@ -542,6 +541,7 @@ static int i801_block_transaction_by_block(struct i801_priv *priv, return -EPROTO; data->block[0] = len; + inb_p(SMBHSTCNT(priv)); /* reset the data buffer index */ for (i = 0; i < len; i++) data->block[i + 1] = inb_p(SMBBLKDAT(priv)); } -- 2.43.0
