1 files changed, 19 insertions, 17 deletions

diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
index 34e75bc8f4cc..7e8fc7c1d4cc 100644
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -105,7 +105,7 @@ static struct old_serial_port old_serial_port[] = {
         SERIAL_PORT_DFNS /* defined in asm/serial.h */
 };
 
-#define UART_NR (ARRAY_SIZE(old_serial_port) + CONFIG_SERIAL_8250_NR_UARTS)
+#define UART_NR CONFIG_SERIAL_8250_NR_UARTS
 
 #ifdef CONFIG_SERIAL_8250_RSA
 
@@ -993,21 +993,24 @@ static void autoconfig_irq(struct uart_8250_port *up)
         up->port.irq = (irq > 0) ? irq : 0;
 }
 
+static inline void __stop_tx(struct uart_8250_port *p)
+{
+        if (p->ier & UART_IER_THRI) {
+                p->ier &= ~UART_IER_THRI;
+                serial_out(p, UART_IER, p->ier);
+        }
+}
+
 static void serial8250_stop_tx(struct uart_port *port, unsigned int tty_stop)
 {
         struct uart_8250_port *up = (struct uart_8250_port *)port;
 
-        if (up->ier & UART_IER_THRI) {
-                up->ier &= ~UART_IER_THRI;
-                serial_out(up, UART_IER, up->ier);
-        }
+        __stop_tx(up);
 
         /*
-         * We only do this from uart_stop - if we run out of
-         * characters to send, we don't want to prevent the
-         * FIFO from emptying.
+         * We really want to stop the transmitter from sending.
          */
-        if (up->port.type == PORT_16C950 && tty_stop) {
+        if (up->port.type == PORT_16C950) {
                 up->acr |= UART_ACR_TXDIS;
                 serial_icr_write(up, UART_ACR, up->acr);
         }
@@ -1031,10 +1034,11 @@ static void serial8250_start_tx(struct uart_port *port, unsigned int tty_start)
                                 transmit_chars(up);
                 }
         }
+
         /*
-         * We only do this from uart_start
+         * Re-enable the transmitter if we disabled it.
          */
-        if (tty_start && up->port.type == PORT_16C950) {
+        if (up->port.type == PORT_16C950 && up->acr & UART_ACR_TXDIS) {
                 up->acr &= ~UART_ACR_TXDIS;
                 serial_icr_write(up, UART_ACR, up->acr);
         }
@@ -1155,7 +1159,7 @@ static _INLINE_ void transmit_chars(struct uart_8250_port *up)
                 return;
         }
         if (uart_circ_empty(xmit) || uart_tx_stopped(&up->port)) {
-                serial8250_stop_tx(&up->port, 0);
+                __stop_tx(up);
                 return;
         }
 
@@ -1174,7 +1178,7 @@ static _INLINE_ void transmit_chars(struct uart_8250_port *up)
         DEBUG_INTR("THRE...");
 
         if (uart_circ_empty(xmit))
-                serial8250_stop_tx(&up->port, 0);
+                __stop_tx(up);
 }
 
 static _INLINE_ void check_modem_status(struct uart_8250_port *up)
@@ -1376,13 +1380,10 @@ static unsigned int serial8250_tx_empty(struct uart_port *port)
 static unsigned int serial8250_get_mctrl(struct uart_port *port)
 {
         struct uart_8250_port *up = (struct uart_8250_port *)port;
-        unsigned long flags;
         unsigned char status;
         unsigned int ret;
 
-        spin_lock_irqsave(&up->port.lock, flags);
         status = serial_in(up, UART_MSR);
-        spin_unlock_irqrestore(&up->port.lock, flags);
 
         ret = 0;
         if (status & UART_MSR_DCD)
@@ -2060,7 +2061,8 @@ static void __init serial8250_isa_init_ports(void)
                 up->port.ops = &serial8250_pops;
         }
 
-        for (i = 0, up = serial8250_ports; i < ARRAY_SIZE(old_serial_port);
+        for (i = 0, up = serial8250_ports;
+             i < ARRAY_SIZE(old_serial_port) && i < UART_NR;
              i++, up++) {
                 up->port.iobase   = old_serial_port[i].port;
                 up->port.irq      = irq_canonicalize(old_serial_port[i].irq);