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    SubjectRe: [PATCH 4.19 144/245] serial: uartps: Wait for tx_empty in console setup
    Hi!

    > From: Raviteja Narayanam <raviteja.narayanam@xilinx.com>
    >
    > [ Upstream commit 42e11948ddf68b9f799cad8c0ddeab0a39da33e8 ]
    >
    > On some platforms, the log is corrupted while console is being
    > registered. It is observed that when set_termios is called, there
    > are still some bytes in the FIFO to be transmitted.
    >
    > So, wait for tx_empty inside cdns_uart_console_setup before calling
    > set_termios.

    > @@ -1246,6 +1247,13 @@ static int cdns_uart_console_setup(struct console *co, char *options)
    > if (options)
    > uart_parse_options(options, &baud, &parity, &bits, &flow);
    >
    > + /* Wait for tx_empty before setting up the console */
    > + time_out = jiffies + usecs_to_jiffies(TX_TIMEOUT);
    > +
    > + while (time_before(jiffies, time_out) &&
    > + cdns_uart_tx_empty(port) != TIOCSER_TEMT)
    > + cpu_relax();
    > +

    So this is spinning for half a second. Could we use msleep(1) instead
    of cpu_relax or something like that?

    Best regards,
    Pavel

    --
    (english) http://www.livejournal.com/~pavelmachek
    (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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