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    SubjectRe: [PATCH AUTOSEL 4.9 64/90] serial: uartps: Wait for tx_empty in console setup
    On Fri, 18 Sep 2020 at 07:55, Sasha Levin <sashal@kernel.org> wrote:
    >
    > 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.
    >
    > Signed-off-by: Raviteja Narayanam <raviteja.narayanam@xilinx.com>
    > Reviewed-by: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
    > Link: https://lore.kernel.org/r/1586413563-29125-2-git-send-email-raviteja.narayanam@xilinx.com
    > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    > Signed-off-by: Sasha Levin <sashal@kernel.org>

    stable rc 4.9 arm64 build broken.

    drivers/tty/serial/xilinx_uartps.c: In function 'cdns_uart_console_setup':
    drivers/tty/serial/xilinx_uartps.c:1286:40: error: 'TX_TIMEOUT'
    undeclared (first use in this function); did you mean 'ETIMEDOUT'?
    time_out = jiffies + usecs_to_jiffies(TX_TIMEOUT);
    ^~~~~~~~~~
    ETIMEDOUT
    drivers/tty/serial/xilinx_uartps.c:1286:40: note: each undeclared
    identifier is reported only once for each function it appears in
    CC drivers/usb/core/port.o
    scripts/Makefile.build:304: recipe for target
    'drivers/tty/serial/xilinx_uartps.o' failed
    make[5]: *** [drivers/tty/serial/xilinx_uartps.o] Error 1

    Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>

    full test log link,
    https://ci.linaro.org/view/lkft/job/openembedded-lkft-linux-stable-rc-4.9/DISTRO=lkft,MACHINE=hikey,label=docker-lkft/996/consoleText


    > ---
    > drivers/tty/serial/xilinx_uartps.c | 8 ++++++++
    > 1 file changed, 8 insertions(+)
    >
    > diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
    > index eb61a07fcbbc3..07ea71a611678 100644
    > --- a/drivers/tty/serial/xilinx_uartps.c
    > +++ b/drivers/tty/serial/xilinx_uartps.c
    > @@ -1268,6 +1268,7 @@ static int cdns_uart_console_setup(struct console *co, char *options)
    > int bits = 8;
    > int parity = 'n';
    > int flow = 'n';
    > + unsigned long time_out;
    >
    > if (co->index < 0 || co->index >= CDNS_UART_NR_PORTS)
    > return -EINVAL;
    > @@ -1281,6 +1282,13 @@ 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();
    > +
    > return uart_set_options(port, co, baud, parity, bits, flow);
    > }
    >
    > --
    > 2.25.1
    >


    --
    Linaro LKFT
    https://lkft.linaro.org

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