From dc00318f64a735001bd7fb097278a1804ac2f52a Mon Sep 17 00:00:00 2001 From: Heiko Stuebner Date: Tue, 16 Sep 2025 11:58:06 +0200 Subject: [PATCH v3 1/4] mfd: qnap-mcu: Calculate the checksum on the actual number of bytes received In the case of an error message, the number of received bytes can be less than originally expected but still contain a valid message. If the transfer itself ended in an error we would exit earlier already. So calculate the checksum on the number of received bytes and not the number of expected bytes. Signed-off-by: Heiko Stuebner --- drivers/mfd/qnap-mcu.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/mfd/qnap-mcu.c b/drivers/mfd/qnap-mcu.c index 2be429a50611..e3210541ec56 100644 --- a/drivers/mfd/qnap-mcu.c +++ b/drivers/mfd/qnap-mcu.c @@ -175,8 +175,8 @@ int qnap_mcu_exec(struct qnap_mcu *mcu, return -ETIMEDOUT; } - crc = qnap_mcu_csum(rx, reply_data_size); - if (crc != rx[reply_data_size]) { + crc = qnap_mcu_csum(rx, reply->received - QNAP_MCU_CHECKSUM_SIZE); + if (crc != rx[reply->received - QNAP_MCU_CHECKSUM_SIZE]) { dev_err(&mcu->serdev->dev, "Invalid Checksum received\n"); return -EIO; } -- 2.47.2