xhci: dbctty: disable ECHO flag by default

commit 2b857d69a5e116150639a0c6c39c86cc329939ee upstream.

When /dev/ttyDBC0 device is created then by default ECHO flag
is set for the terminal device. However if data arrives from
a peer before application using /dev/ttyDBC0 applies its set
of terminal flags then the arriving data will be echoed which
might not be desired behavior.

Fixes: 4521f1613940 ("xhci: dbctty: split dbc tty driver registration and unregistration functions.")
Cc: stable <stable@kernel.org>
Signed-off-by: Łukasz Bartosik <ukaszb@chromium.org>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/stable/20250610111802.18742-1-ukaszb%40chromium.org
Link: https://lore.kernel.org/r/20250627144127.3889714-4-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/host/xhci-dbgtty.c b/drivers/usb/host/xhci-dbgtty.c
index 18bcc96853ae106f2fe4574ed256ae7beefa0cc8..68c01a3f999a0527594e02f1c768372802b1d727 100644 (file)
--- a/drivers/usb/host/xhci-dbgtty.c
+++ b/drivers/usb/host/xhci-dbgtty.c
@@ -537,6 +537,7 @@ static int dbc_tty_init(void)
        dbc_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
        dbc_tty_driver->subtype = SERIAL_TYPE_NORMAL;
        dbc_tty_driver->init_termios = tty_std_termios;
+       dbc_tty_driver->init_termios.c_lflag &= ~ECHO;
        dbc_tty_driver->init_termios.c_cflag =
                        B9600 | CS8 | CREAD | HUPCL | CLOCAL;
        dbc_tty_driver->init_termios.c_ispeed = 9600;