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Groups > linux.kernel > #1421208

[RFC PATCH] tty: serial: msm_serial: Don't reset uart on set_termios

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Upon opening the tty, uart_open() ends up calling msm_set_baud_rate()
which resets the uart block. If this happens as we're coming out of
msm_console_write() a full fifo worth of console output will be
discarded.

Cc: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
---

As reported here:
https://bugs.96boards.org/show_bug.cgi?id=378

 drivers/tty/serial/msm_serial.c | 18 ------------------
 1 file changed, 18 deletions(-)

diff --git a/drivers/tty/serial/msm_serial.c b/drivers/tty/serial/msm_serial.c
index b7d80bd57db9..93a10ac44933 100644
--- a/drivers/tty/serial/msm_serial.c
+++ b/drivers/tty/serial/msm_serial.c
@@ -813,23 +813,6 @@ static unsigned int msm_get_mctrl(struct uart_port *port)
 	return TIOCM_CAR | TIOCM_CTS | TIOCM_DSR | TIOCM_RTS;
 }
 
-static void msm_reset(struct uart_port *port)
-{
-	struct msm_port *msm_port = UART_TO_MSM(port);
-
-	/* reset everything */
-	msm_write(port, UART_CR_CMD_RESET_RX, UART_CR);
-	msm_write(port, UART_CR_CMD_RESET_TX, UART_CR);
-	msm_write(port, UART_CR_CMD_RESET_ERR, UART_CR);
-	msm_write(port, UART_CR_CMD_RESET_BREAK_INT, UART_CR);
-	msm_write(port, UART_CR_CMD_RESET_CTS, UART_CR);
-	msm_write(port, UART_CR_CMD_SET_RFR, UART_CR);
-
-	/* Disable DM modes */
-	if (msm_port->is_uartdm)
-		msm_write(port, 0, UARTDM_DMEN);
-}
-
 static void msm_set_mctrl(struct uart_port *port, unsigned int mctrl)
 {
 	unsigned int mr;
@@ -972,7 +955,6 @@ static int msm_set_baud_rate(struct uart_port *port, unsigned int baud,
 	msm_write(port, 10, UART_TFWR);
 
 	msm_write(port, UART_CR_CMD_PROTECTION_EN, UART_CR);
-	msm_reset(port);
 
 	/* Enable RX and TX */
 	msm_write(port, UART_CR_TX_ENABLE | UART_CR_RX_ENABLE, UART_CR);
-- 
2.5.0

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[RFC PATCH] tty: serial: msm_serial: Don't reset uart on set_termios Bjorn Andersson <bjorn.andersson@linaro.org> - 2016-06-13 21:10 +0200
  Re: [RFC PATCH] tty: serial: msm_serial: Don't reset uart on set_termios Pramod Gurav <pramod.gurav@linaro.org> - 2016-06-15 15:00 +0200
  Re: [RFC PATCH] tty: serial: msm_serial: Don't reset uart on  set_termios Stephen Boyd <sboyd@codeaurora.org> - 2016-06-16 03:20 +0200
  [PATCH v2] tty: serial: msm: Don't reconfigure same baud rate Bjorn Andersson <bjorn.andersson@linaro.org> - 2016-06-16 20:30 +0200
    Re: [PATCH v2] tty: serial: msm: Don't reconfigure same baud rate Nicolas Dechesne <nicolas.dechesne@linaro.org> - 2016-06-17 12:10 +0200
      Re: [PATCH v2] tty: serial: msm: Don't reconfigure same baud rate Nicolas Dechesne <nicolas.dechesne@linaro.org> - 2016-06-21 12:20 +0200
        Re: [PATCH v2] tty: serial: msm: Don't reconfigure same baud rate Srinivas Kandagatla <srinivas.kandagatla@linaro.org> - 2016-06-22 12:10 +0200
    Re: [PATCH v2] tty: serial: msm: Don't reconfigure same baud rate Stephen Boyd <sboyd@codeaurora.org> - 2016-06-21 02:00 +0200

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