On Fri, Jun 28, 2019 at 10:33:39AM -0400, Robert Middleton wrote:
> Hi,
>
> I have fixed the problem for my use-case with the following patch to
> not clear the FIFOs if there is still data to be transmitted:
>
> diff --git a/drivers/tty/serial/8250/8250_port.c
> b/drivers/tty/serial/8250/8250_port.c
> index d2f3310abe54..569a76d1b00a 100644
> --- a/drivers/tty/serial/8250/8250_port.c
> +++ b/drivers/tty/serial/8250/8250_port.c
> @@ -2441,7 +2441,10 @@ void serial8250_do_shutdown(struct uart_port *port)
> */
> serial_port_out(port, UART_LCR,
> serial_port_in(port, UART_LCR) & ~UART_LCR_SBC);
> - serial8250_clear_fifos(up);
> + if (serial_in(up, UART_LSR) & UART_LSR_TEMT){
> + /* Check if transmitter is empty before clearing FIFOs */
> + serial8250_clear_fifos(up);
> + }
>
> #ifdef CONFIG_SERIAL_8250_RSA
> /*
>
> I'm not sure if this is correct/the best way to do it, since I am not
> sure if this is common to all drivers under 8250 or only for the Exar
> chip. I can also provide a proper patch via e-mail if that makes
> sense.
A proper patch makes the most sense please.
thanks,
greg k-h
