On Tue, 29 Sep 2020 at 01:41, Naresh Kamboju [off-list ref] wrote:

On Fri, 18 Sep 2020 at 07:55, Sasha Levin [off-list ref] wrote:

quoted

From: Raviteja Narayanam <redacted>

[ 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 <redacted>
Reviewed-by: Shubhrajyoti Datta <redacted>
Link: https://lore.kernel.org/r/1586413563-29125-2-git-send-email-raviteja.narayanam@xilinx.com (local)
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

stable rc 4.9 arm64 build broken.

and stable rc 4.9 arm 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 <redacted>

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

quoted

---
 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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