On Thu, Feb 19, 2015 at 03:38:39PM +0200, Jari Ruusu wrote:
> On 2/19/15, Johan Hovold <jo...@kernel.org> wrote:
> > What happens when you reopen the port? Is the break state cleared then?
> 
> Stuck "break" signal is not cleared on re-open.
> 
> To clear it, you need to poke it with ioctl(fd, TIOCCBRK, 0)
> or disconnect the device.

That's definitely a bug.

Care to test the patch below?

Thanks,
Johan


>From ee3f2d35adc59822d72f3908078da7f361c26577 Mon Sep 17 00:00:00 2001
From: Johan Hovold <jo...@kernel.org>
Date: Fri, 20 Feb 2015 10:05:51 +0700
Subject: [PATCH] USB: pl2303: disable break on shutdown

Currently an enabled break state is not disabled on final close nor on
re-open and has to be disabled manually.

Fix this by disabling break on port shutdown.

Reported-by: Jari Ruusu <jariru...@users.sourceforge.net>
Signed-off-by: Johan Hovold <jo...@kernel.org>
---
 drivers/usb/serial/pl2303.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/drivers/usb/serial/pl2303.c b/drivers/usb/serial/pl2303.c
index 0f872e6b2c87..f6fe4737185d 100644
--- a/drivers/usb/serial/pl2303.c
+++ b/drivers/usb/serial/pl2303.c
@@ -132,6 +132,7 @@ MODULE_DEVICE_TABLE(usb, id_table);
 #define UART_OVERRUN_ERROR             0x40
 #define UART_CTS                       0x80
 
+static void pl2303_set_break(struct usb_serial_port *port, bool enable);
 
 enum pl2303_type {
        TYPE_01,        /* Type 0 and 1 (difference unknown) */
@@ -613,6 +614,7 @@ static void pl2303_dtr_rts(struct usb_serial_port *port, 
int on)
 
 static void pl2303_close(struct usb_serial_port *port)
 {
+       pl2303_set_break(port, false);
        usb_serial_generic_close(port);
        usb_kill_urb(port->interrupt_in_urb);
 }
@@ -741,17 +743,16 @@ static int pl2303_ioctl(struct tty_struct *tty,
        return -ENOIOCTLCMD;
 }
 
-static void pl2303_break_ctl(struct tty_struct *tty, int break_state)
+static void pl2303_set_break(struct usb_serial_port *port, bool enable)
 {
-       struct usb_serial_port *port = tty->driver_data;
        struct usb_serial *serial = port->serial;
        u16 state;
        int result;
 
-       if (break_state == 0)
-               state = BREAK_OFF;
-       else
+       if (enable)
                state = BREAK_ON;
+       else
+               state = BREAK_OFF;
 
        dev_dbg(&port->dev, "%s - turning break %s\n", __func__,
                        state == BREAK_OFF ? "off" : "on");
@@ -763,6 +764,13 @@ static void pl2303_break_ctl(struct tty_struct *tty, int 
break_state)
                dev_err(&port->dev, "error sending break = %d\n", result);
 }
 
+static void pl2303_break_ctl(struct tty_struct *tty, int state)
+{
+       struct usb_serial_port *port = tty->driver_data;
+
+       pl2303_set_break(port, state);
+}
+
 static void pl2303_update_line_status(struct usb_serial_port *port,
                                      unsigned char *data,
                                      unsigned int actual_length)
-- 
2.0.5

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