[PATCH] serial: make sure UART is powered up when dumping MCTRL status

[firefly-linux-kernel-4.4.55.git] / drivers / serial / serial_core.c

diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c
index f84982e508c7efc7e2eb6bcdca37f95ee22e8b67..66fdd3b2b9586c349935402a6ef4a4968eca040c 100644 (file)
--- a/drivers/serial/serial_core.c
+++ b/drivers/serial/serial_core.c
@@ -1660,6 +1660,7 @@ static const char *uart_type(struct uart_port *port)
 static int uart_line_info(char *buf, struct uart_driver *drv, int i)
 {
        struct uart_state *state = drv->state + i;
+       int pm_state;
        struct uart_port *port = state->port;
        char stat_buf[32];
        unsigned int status;
@@ -1682,9 +1683,16 @@ static int uart_line_info(char *buf, struct uart_driver *drv, int i)
 
        if(capable(CAP_SYS_ADMIN))
        {
+               mutex_lock(&state->mutex);
+               pm_state = state->pm_state;
+               if (pm_state)
+                       uart_change_pm(state, 0);
                spin_lock_irq(&port->lock);
                status = port->ops->get_mctrl(port);
                spin_unlock_irq(&port->lock);
+               if (pm_state)
+                       uart_change_pm(state, pm_state);
+               mutex_unlock(&state->mutex);
 
                ret += sprintf(buf + ret, " tx:%d rx:%d",
                                port->icount.tx, port->icount.rx);
@@ -2100,6 +2108,9 @@ uart_configure_port(struct uart_driver *drv, struct uart_state *state,
 
                uart_report_port(drv, port);
 
+               /* Power up port for set_mctrl() */
+               uart_change_pm(state, 0);
+
                /*
                 * Ensure that the modem control lines are de-activated.
                 * We probably don't need a spinlock around this, but