Commit e8376633 authored Mar 13, 2020 by Douglas Anderson Committed by Greg Kroah-Hartman Mar 14, 2020

tty: serial: qcom_geni_serial: No need to stop tx/rx on UART shutdown

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: c4f52879 ("tty: serial: msm_geni_serial: Add serial driver support for GENI based QUP")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20200313134635.1.Icf54c533065306b02b880c46dfd401d8db34e213@changeid

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 1aa6e058

drivers/tty/serial/qcom_geni_serial.c

+0 −6

Original line number	Diff line number	Diff line
		@@ -825,17 +825,11 @@ 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)

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