Hi Michal

On 23/04/18 10:18, Michal Simek wrote:

device->baud is always non zero value because it is checked already in early_serial8250_setup() before init_port is called.

True, currently init_port is only called from the one location and so the test is a little redundant, though I don't see the harm in testing both inputs to the divisor calculation immediately before use such that any future call path avoids setting a bad divisor.

Fixes: 0ff3ab701963 ("serial: 8250_early: Only set divisor if valid clk & baud") Cc: stable stable@vger.kernel.org

Even if the test is dropped going forward, I wouldn't consider it's presence a "bug" such that a fix needs to be backported.

Thanks, Matt

Signed-off-by: Michal Simek michal.simek@xilinx.com

drivers/tty/serial/8250/8250_early.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/serial/8250/8250_early.c b/drivers/tty/serial/8250/8250_early.c index ae6a256524d8..5cd8c36c8fcc 100644 --- a/drivers/tty/serial/8250/8250_early.c +++ b/drivers/tty/serial/8250/8250_early.c @@ -122,7 +122,7 @@ static void __init init_port(struct earlycon_device *device) serial8250_early_out(port, UART_FCR, 0); /* no fifo */ serial8250_early_out(port, UART_MCR, 0x3); /* DTR + RTS */

• if (port->uartclk && device->baud) {

• if (port->uartclk) { divisor = DIV_ROUND_CLOSEST(port->uartclk, 16 * device->baud); c = serial8250_early_in(port, UART_LCR); serial8250_early_out(port, UART_LCR, c | UART_LCR_DLAB);