diff --git a/linux-2.6.22/drivers/serial/serial_core.c b/linux-2.6.22/drivers/serial/serial_core.c
index 326020f..839d41c 100644
--- a/linux-2.6.22/drivers/serial/serial_core.c
+++ b/linux-2.6.22/drivers/serial/serial_core.c
@@ -104,9 +104,9 @@ static void uart_start(struct tty_struct *tty)
 	struct uart_port *port = state->port;
 	unsigned long flags;
 
-	spin_lock_irqsave(&port->lock, flags);
+	spin_lock_irqsave(&port->info->lock, flags);
 	__uart_start(tty);
-	spin_unlock_irqrestore(&port->lock, flags);
+	spin_unlock_irqrestore(&port->info->lock, flags);
 }
 
 static void uart_tasklet_action(unsigned long data)
@@ -453,12 +453,12 @@ __uart_put_char(struct uart_port *port, struct circ_buf *circ, unsigned char c)
 	if (!circ->buf)
 		return;
 
-	spin_lock_irqsave(&port->lock, flags);
+	spin_lock_irqsave(&port->info->lock, flags);
 	if (uart_circ_chars_free(circ) != 0) {
 		circ->buf[circ->head] = c;
 		circ->head = (circ->head + 1) & (UART_XMIT_SIZE - 1);
 	}
-	spin_unlock_irqrestore(&port->lock, flags);
+	spin_unlock_irqrestore(&port->info->lock, flags);
 }
 
 static void uart_put_char(struct tty_struct *tty, unsigned char ch)
@@ -497,7 +497,7 @@ uart_write(struct tty_struct *tty, const unsigned char *buf, int count)
 	if (!circ->buf)
 		return 0;
 
-	spin_lock_irqsave(&port->lock, flags);
+	spin_lock_irqsave(&port->info->lock, flags);
 	while (1) {
 		c = CIRC_SPACE_TO_END(circ->head, circ->tail, UART_XMIT_SIZE);
 		if (count < c)
@@ -510,7 +510,7 @@ uart_write(struct tty_struct *tty, const unsigned char *buf, int count)
 		count -= c;
 		ret += c;
 	}
-	spin_unlock_irqrestore(&port->lock, flags);
+	spin_unlock_irqrestore(&port->info->lock, flags);
 
 	uart_start(tty);
 	return ret;
@@ -547,9 +547,9 @@ static void uart_flush_buffer(struct tty_struct *tty)
 
 	pr_debug("uart_flush_buffer(%d) called\n", tty->index);
 
-	spin_lock_irqsave(&port->lock, flags);
+	spin_lock_irqsave(&port->info->lock, flags);
 	uart_circ_clear(&state->info->xmit);
-	spin_unlock_irqrestore(&port->lock, flags);
+	spin_unlock_irqrestore(&port->info->lock, flags);
 	tty_wakeup(tty);
 }
 
@@ -568,9 +568,9 @@ static void uart_send_xchar(struct tty_struct *tty, char ch)
 	else {
 		port->x_char = ch;
 		if (ch) {
-			spin_lock_irqsave(&port->lock, flags);
+			spin_lock_irqsave(&port->info->lock, flags);
 			port->ops->start_tx(port);
-			spin_unlock_irqrestore(&port->lock, flags);
+			spin_unlock_irqrestore(&port->info->lock, flags);
 		}
 	}
 }
@@ -1525,6 +1525,10 @@ static struct uart_state *uart_get(struct uart_driver *drv, int line)
 			init_waitqueue_head(&state->info->open_wait);
 			init_waitqueue_head(&state->info->delta_msr_wait);
 
+			/* majiuyue: seperate port->lock and info->lock */
+ 			spin_lock_init(&state->info->lock);
+			lockdep_set_class(&state->info->lock, &port_lock_key);
+
 			/*
 			 * Link the info into the other structures.
 			 */
diff --git a/linux-2.6.22/include/linux/serial_core.h b/linux-2.6.22/include/linux/serial_core.h
index 7f2c99d..55ded23 100644
--- a/linux-2.6.22/include/linux/serial_core.h
+++ b/linux-2.6.22/include/linux/serial_core.h
@@ -322,6 +322,7 @@ typedef unsigned int __bitwise__ uif_t;
  * stuff here.
  */
 struct uart_info {
+	spinlock_t		lock;		/* majiuyue: uart info lock */
 	struct tty_struct	*tty;
 	struct circ_buf		xmit;
 	uif_t			flags;