From: Johan Hovold johan@kernel.org
commit 188c9c2e0c7f4ae864113f80c40bafb394062271 upstream.
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: 3aacac02f385 ("USB: serial: f81534: add high baud rate support") Cc: stable@vger.kernel.org # 4.16 Cc: Ji-Ze Hong (Peter Hong) hpeter@gmail.com Reviewed-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Johan Hovold johan@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/usb/serial/f81534.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-)
--- a/drivers/usb/serial/f81534.c +++ b/drivers/usb/serial/f81534.c @@ -538,9 +538,6 @@ static int f81534_submit_writer(struct u
static u32 f81534_calc_baud_divisor(u32 baudrate, u32 clockrate) { - if (!baudrate) - return 0; - /* Round to nearest divisor */ return DIV_ROUND_CLOSEST(clockrate, baudrate); } @@ -570,9 +567,14 @@ static int f81534_set_port_config(struct u32 baud_list[] = {baudrate, old_baudrate, F81534_DEFAULT_BAUD_RATE};
for (i = 0; i < ARRAY_SIZE(baud_list); ++i) { - idx = f81534_find_clk(baud_list[i]); + baudrate = baud_list[i]; + if (baudrate == 0) { + tty_encode_baud_rate(tty, 0, 0); + return 0; + } + + idx = f81534_find_clk(baudrate); if (idx >= 0) { - baudrate = baud_list[i]; tty_encode_baud_rate(tty, baudrate, baudrate); break; }