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Subject[PATCH 1/2] tty: serial: qcom_geni_serial: No need to stop tx/rx on UART shutdown
Date
On a board using qcom_geni_serial I found that I could no longer
interact with kdb if I got a crash after the "agetty" running on the
same serial port was killed. This meant that various classes of
crashes that happened at reboot time were undebuggable.

Reading through the code, I couldn't figure out why qcom_geni_serial
felt the need to run so much code at port shutdown time. All we need
to do is disable the interrupt.

After I make this change then a hardcoded kgdb_breakpoint in some late
shutdown code now allows me to interact with the debugger. I also
could freely close / re-open the port without problems.

Fixes: c4f528795d1a ("tty: serial: msm_geni_serial: Add serial driver support for GENI based QUP")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
---

drivers/tty/serial/qcom_geni_serial.c | 6 ------
1 file changed, 6 deletions(-)

diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
index 272bae0eebc7..09d8612517aa 100644
--- a/drivers/tty/serial/qcom_geni_serial.c
+++ b/drivers/tty/serial/qcom_geni_serial.c
@@ -827,17 +827,11 @@ static void get_tx_fifo_size(struct qcom_geni_serial_port *port)

static void qcom_geni_serial_shutdown(struct uart_port *uport)
{
- unsigned long flags;
-
/* Stop the console before stopping the current tx */
if (uart_console(uport))
console_stop(uport->cons);

disable_irq(uport->irq);
- spin_lock_irqsave(&uport->lock, flags);
- qcom_geni_serial_stop_tx(uport);
- qcom_geni_serial_stop_rx(uport);
- spin_unlock_irqrestore(&uport->lock, flags);
}

static int qcom_geni_serial_port_setup(struct uart_port *uport)
--
2.25.1.481.gfbce0eb801-goog
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