Re: [PATCH 3/4] serial: 8250: Handle case port doesn't have TEMT interrupt using em485.

From: Alan Cox
Date: Wed Jun 13 2018 - 13:01:12 EST


> + } else {
> + while ((lsr & BOTH_EMPTY) != BOTH_EMPTY) {
> + lsr = serial_in(p, UART_LSR);
> + cpu_relax();
> + }
> + }

This still needs a timeout in case some kind of hardware flow control line
is asserted and therefore the byte is staying put.

Alan