1 files changed, 15 insertions, 0 deletions

diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
index b4b39811b44..a0127e93ade 100644
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -137,6 +137,7 @@ struct uart_8250_port {
         unsigned char           mcr;
         unsigned char           mcr_mask;       /* mask of user bits */
         unsigned char           mcr_force;      /* mask of forced bits */
+        unsigned char           cur_iotype;     /* Running I/O type */
 
         /*
          * Some bits in registers are cleared on a read, so they must
@@ -471,6 +472,7 @@ static void io_serial_out(struct uart_port *p, int offset, int value)
 
 static void set_io_from_upio(struct uart_port *p)
 {
+        struct uart_8250_port *up = (struct uart_8250_port *)p;
         switch (p->iotype) {
         case UPIO_HUB6:
                 p->serial_in = hub6_serial_in;
@@ -509,6 +511,8 @@ static void set_io_from_upio(struct uart_port *p)
                 p->serial_out = io_serial_out;
                 break;
         }
+        /* Remember loaded iotype */
+        up->cur_iotype = p->iotype;
 }
 
 static void
@@ -1937,6 +1941,9 @@ static int serial8250_startup(struct uart_port *port)
         up->capabilities = uart_config[up->port.type].flags;
         up->mcr = 0;
 
+        if (up->port.iotype != up->cur_iotype)
+                set_io_from_upio(port);
+
         if (up->port.type == PORT_16C950) {
                 /* Wake up and initialize UART */
                 up->acr = 0;
@@ -2563,6 +2570,9 @@ static void serial8250_config_port(struct uart_port *port, int flags)
         if (ret < 0)
                 probeflags &= ~PROBE_RSA;
 
+        if (up->port.iotype != up->cur_iotype)
+                set_io_from_upio(port);
+
         if (flags & UART_CONFIG_TYPE)
                 autoconfig(up, probeflags);
         if (up->port.type != PORT_UNKNOWN && flags & UART_CONFIG_IRQ)
@@ -2671,6 +2681,11 @@ serial8250_register_ports(struct uart_driver *drv, struct device *dev)
 {
         int i;
 
+        for (i = 0; i < nr_uarts; i++) {
+                struct uart_8250_port *up = &serial8250_ports[i];
+                up->cur_iotype = 0xFF;
+        }
+
         serial8250_isa_init_ports();
 
         for (i = 0; i < nr_uarts; i++) {