The driver leaves the line speed unchanged in case a requested speed is not supported. Make sure to handle the case where the current speed is B0 (hangup) without dividing by zero when determining the clock source.

Fixes: 268ddb5e9b62 ("USB: serial: f81232: add high baud rate support") Cc: stable@vger.kernel.org # 5.2 Cc: Ji-Ze Hong (Peter Hong) hpeter@gmail.com Signed-off-by: Johan Hovold johan@kernel.org --- drivers/usb/serial/f81232.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/usb/serial/f81232.c b/drivers/usb/serial/f81232.c index 2dd58cd9f0cc..891fb1fe69df 100644 --- a/drivers/usb/serial/f81232.c +++ b/drivers/usb/serial/f81232.c @@ -130,9 +130,6 @@ static u8 const clock_table[] = { F81232_CLK_1_846_MHZ, F81232_CLK_14_77_MHZ,

static int calc_baud_divisor(speed_t baudrate, speed_t clockrate) { - if (!baudrate) - return 0; - return DIV_ROUND_CLOSEST(clockrate, baudrate); }

@@ -498,9 +495,14 @@ static void f81232_set_baudrate(struct tty_struct *tty, speed_t baud_list[] = { baudrate, old_baudrate, F81232_DEF_BAUDRATE };

for (i = 0; i < ARRAY_SIZE(baud_list); ++i) { - idx = f81232_find_clk(baud_list[i]); + baudrate = baud_list[i]; + if (baudrate == 0) { + tty_encode_baud_rate(tty, 0, 0); + return; + } + + idx = f81232_find_clk(baudrate); if (idx >= 0) { - baudrate = baud_list[i]; tty_encode_baud_rate(tty, baudrate, baudrate); break; }