4.17-stable review patch. If anyone has any objections, please let me know. ------------------ From: Roman Fietze <roman.fietze@xxxxxxxxxxxxx> commit 393753b217f05474e714aea36c37501546ed1202 upstream. Inside m_can_chip_config(), when setting up the new value of the CCCR, the CCCR_NISO bit is not cleared like the others, CCCR_TEST, CCCR_MON, CCCR_BRSE and CCCR_FDOE, before checking the can.ctrlmode bits for CAN_CTRLMODE_FD_NON_ISO. This way once the controller was configured for CAN_CTRLMODE_FD_NON_ISO, this mode could never be cleared again. This fix is only relevant for controllers with version 3.1.x or 3.2.x. Older versions do not support NISO. Signed-off-by: Roman Fietze <roman.fietze@xxxxxxxxxxxxx> Cc: linux-stable <stable@xxxxxxxxxxxxxxx> Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/net/can/m_can/m_can.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/net/can/m_can/m_can.c +++ b/drivers/net/can/m_can/m_can.c @@ -1111,7 +1111,8 @@ static void m_can_chip_config(struct net } else { /* Version 3.1.x or 3.2.x */ - cccr &= ~(CCCR_TEST | CCCR_MON | CCCR_BRSE | CCCR_FDOE); + cccr &= ~(CCCR_TEST | CCCR_MON | CCCR_BRSE | CCCR_FDOE | + CCCR_NISO); /* Only 3.2.x has NISO Bit implemented */ if (priv->can.ctrlmode & CAN_CTRLMODE_FD_NON_ISO)