Move HUPCL handling to port shutdown so that DTR is dropped also on hang up (tty_port_close is a noop for hung-up ports). Also do not try to drop DTR for uninitialised ports where it has never been raised (e.g. after a failed open). Nine drivers currently call tty_port_close_start directly (rather than through tty_port_close) and seven of them lower DTR as part of their close (if the port has been initialised). Fixup the remaining two drivers so that it continues to be lowered also on normal (non-HUP) close. [ Note that most of those other seven drivers did not expect DTR to have been dropped by tty_port_close_start in the first place. ] Signed-off-by: Johan Hovold <jhovold@xxxxxxxxx> --- drivers/tty/mxser.c | 4 ++++ drivers/tty/n_gsm.c | 4 ++++ drivers/tty/tty_port.c | 23 +++++++++++++---------- 3 files changed, 21 insertions(+), 10 deletions(-) diff --git a/drivers/tty/mxser.c b/drivers/tty/mxser.c index 484b6a3..c547887 100644 --- a/drivers/tty/mxser.c +++ b/drivers/tty/mxser.c @@ -1084,6 +1084,10 @@ static void mxser_close(struct tty_struct *tty, struct file *filp) mutex_lock(&port->mutex); mxser_close_port(port); mxser_flush_buffer(tty); + if (test_bit(ASYNCB_INITIALIZED, &port->flags)) { + if (tty->termios.c_cflag & HUPCL) + tty_port_lower_dtr_rts(port); + } mxser_shutdown_port(port); clear_bit(ASYNCB_INITIALIZED, &port->flags); mutex_unlock(&port->mutex); diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c index 4a43ef5d7..049013e 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -2968,6 +2968,10 @@ static void gsmtty_close(struct tty_struct *tty, struct file *filp) if (tty_port_close_start(&dlci->port, tty, filp) == 0) goto out; gsm_dlci_begin_close(dlci); + if (test_bit(ASYNCB_INITIALIZED, &dlci->port.flags)) { + if (tty->termios.c_cflag & HUPCL) + tty_port_lower_dtr_rts(&dlci->port); + } tty_port_close_end(&dlci->port, tty); tty_port_tty_set(&dlci->port, NULL); out: diff --git a/drivers/tty/tty_port.c b/drivers/tty/tty_port.c index 57a061e..506f579 100644 --- a/drivers/tty/tty_port.c +++ b/drivers/tty/tty_port.c @@ -198,15 +198,25 @@ EXPORT_SYMBOL(tty_port_tty_set); static void tty_port_shutdown(struct tty_port *port) { + struct tty_struct *tty = tty_port_tty_get(port); + mutex_lock(&port->mutex); if (port->console) goto out; if (test_and_clear_bit(ASYNCB_INITIALIZED, &port->flags)) { + /* + * Drop DTR/RTS if HUPCL is set. This causes any attached + * modem to hang up the line. + */ + if (!tty || tty->termios.c_cflag & HUPCL) + tty_port_lower_dtr_rts(port); + if (port->ops->shutdown) port->ops->shutdown(port); } out: + tty_kref_put(tty); mutex_unlock(&port->mutex); } @@ -225,15 +235,13 @@ void tty_port_hangup(struct tty_port *port) spin_lock_irqsave(&port->lock, flags); port->count = 0; port->flags &= ~ASYNC_NORMAL_ACTIVE; - if (port->tty) { + if (port->tty) set_bit(TTY_IO_ERROR, &port->tty->flags); - tty_kref_put(port->tty); - } - port->tty = NULL; spin_unlock_irqrestore(&port->lock, flags); + tty_port_shutdown(port); + tty_port_tty_set(port, NULL); wake_up_interruptible(&port->open_wait); wake_up_interruptible(&port->delta_msr_wait); - tty_port_shutdown(port); } EXPORT_SYMBOL(tty_port_hangup); @@ -452,11 +460,6 @@ int tty_port_close_start(struct tty_port *port, /* Flush the ldisc buffering */ tty_ldisc_flush(tty); - /* Drop DTR/RTS if HUPCL is set. This causes any attached modem to - hang up the line */ - if (tty->termios.c_cflag & HUPCL) - tty_port_lower_dtr_rts(port); - /* Don't call port->drop for the last reference. Callers will want to drop the last active reference in ->shutdown() or the tty shutdown path */ -- 1.8.1.1 -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html