X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=drivers%2Fserial%2F8250.c;h=27f34a9f9cb750297ea6527ce5d181b47b0ca660;hb=d26acd92fa990764b72608a68224f46fac377032;hp=ce948b66bbd428147d6b4ae1b09c9819b7ae41dd;hpb=df4f4dd429870f435f8d5d9d561db029a29f063b;p=linux-2.6

diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
index ce948b66bb..9ccc563d87 100644
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -1293,7 +1293,18 @@ receive_chars(struct uart_8250_port *up, unsigned int *status)
 	char flag;
 
 	do {
-		ch = serial_inp(up, UART_RX);
+		if (likely(lsr & UART_LSR_DR))
+			ch = serial_inp(up, UART_RX);
+		else
+			/*
+			 * Intel 82571 has a Serial Over Lan device that will
+			 * set UART_LSR_BI without setting UART_LSR_DR when
+			 * it receives a break. To avoid reading from the
+			 * receive buffer without UART_LSR_DR bit set, we
+			 * just force the read character to be 0
+			 */
+			ch = 0;
+
 		flag = TTY_NORMAL;
 		up->port.icount.rx++;
 
@@ -1342,7 +1353,7 @@ receive_chars(struct uart_8250_port *up, unsigned int *status)
 
 ignore_char:
 		lsr = serial_inp(up, UART_LSR);
-	} while ((lsr & UART_LSR_DR) && (max_count-- > 0));
+	} while ((lsr & (UART_LSR_DR | UART_LSR_BI)) && (max_count-- > 0));
 	spin_unlock(&up->port.lock);
 	tty_flip_buffer_push(tty);
 	spin_lock(&up->port.lock);
@@ -1425,7 +1436,7 @@ serial8250_handle_port(struct uart_8250_port *up)
 
 	DEBUG_INTR("status = %x...", status);
 
-	if (status & UART_LSR_DR)
+	if (status & (UART_LSR_DR | UART_LSR_BI))
 		receive_chars(up, &status);
 	check_modem_status(up);
 	if (status & UART_LSR_THRE)
@@ -1875,6 +1886,8 @@ static int serial8250_startup(struct uart_port *port)
 		 * allow register changes to become visible.
 		 */
 		spin_lock_irqsave(&up->port.lock, flags);
+		if (up->port.flags & UPF_SHARE_IRQ)
+			disable_irq_nosync(up->port.irq);
 
 		wait_for_xmitr(up, UART_LSR_THRE);
 		serial_out_sync(up, UART_IER, UART_IER_THRI);
@@ -1886,6 +1899,8 @@ static int serial8250_startup(struct uart_port *port)
 		iir = serial_in(up, UART_IIR);
 		serial_out(up, UART_IER, 0);
 
+		if (up->port.flags & UPF_SHARE_IRQ)
+			enable_irq(up->port.irq);
 		spin_unlock_irqrestore(&up->port.lock, flags);
 
 		/*
@@ -1893,14 +1908,22 @@ static int serial8250_startup(struct uart_port *port)
 		 * kick the UART on a regular basis.
 		 */
 		if (!(iir1 & UART_IIR_NO_INT) && (iir & UART_IIR_NO_INT)) {
+			up->bugs |= UART_BUG_THRE;
 			pr_debug("ttyS%d - using backup timer\n", port->line);
-			up->timer.function = serial8250_backup_timeout;
-			up->timer.data = (unsigned long)up;
-			mod_timer(&up->timer, jiffies +
-				poll_timeout(up->port.timeout) + HZ / 5);
 		}
 	}
 
+	/*
+	 * The above check will only give an accurate result the first time
+	 * the port is opened so this value needs to be preserved.
+	 */
+	if (up->bugs & UART_BUG_THRE) {
+		up->timer.function = serial8250_backup_timeout;
+		up->timer.data = (unsigned long)up;
+		mod_timer(&up->timer, jiffies +
+			  poll_timeout(up->port.timeout) + HZ / 5);
+	}
+
 	/*
 	 * If the "interrupt" for this port doesn't correspond with any
 	 * hardware interrupt, we use a timer-based system.  The original