diff -rup --exclude '*SCCS*' --exclude BitKeeper linux.orig/drivers/char/serial.c linux/drivers/char/serial.c
--- linux.orig/drivers/char/serial.c	Wed Mar  9 17:47:18 2005
+++ linux/drivers/char/serial.c	Thu Mar 17 12:04:54 2005
@@ -140,10 +140,10 @@ static char *serial_revdate = "2001-07-0
 
 /* Set of debugging defines */
 
-#undef SERIAL_DEBUG_INTR
+#define SERIAL_DEBUG_INTR
 #undef SERIAL_DEBUG_OPEN
 #undef SERIAL_DEBUG_FLOW
-#undef SERIAL_DEBUG_RS_WAIT_UNTIL_SENT
+#define SERIAL_DEBUG_RS_WAIT_UNTIL_SENT
 #undef SERIAL_DEBUG_PCI
 #undef SERIAL_DEBUG_AUTOCONF
 
@@ -265,6 +265,10 @@ static int serial_refcount;
 
 static struct timer_list serial_timer;
 
+extern pid_t watched_pid;
+extern void dbg_addmsg(char *fmt, ...);
+#define printk(...) dbg_addmsg(__VA_ARGS__)
+
 /* serial subtype definitions */
 #ifndef SERIAL_TYPE_NORMAL
 #define SERIAL_TYPE_NORMAL	1
@@ -927,7 +931,7 @@ static void rs_interrupt_single(int irq,
 		    ((iir & UART_IIR_ID) == UART_IIR_THRI))
 			transmit_chars(info, 0);
 		if (pass_counter++ > RS_ISR_PASS_LIMIT) {
-#if SERIAL_DEBUG_INTR
+#ifdef SERIAL_DEBUG_INTR
 			printk("rs_single loop break.\n");
 #endif
 			break;
@@ -2942,12 +2946,12 @@ static void rs_wait_until_sent(struct tt
 	if (!timeout || timeout > 2*info->timeout)
 		timeout = 2*info->timeout;
 #ifdef SERIAL_DEBUG_RS_WAIT_UNTIL_SENT
-	printk("In rs_wait_until_sent(%d) check=%lu...", timeout, char_time);
-	printk("jiff=%lu...", jiffies);
+	if (tty->driver.type != TTY_DRIVER_TYPE_PTY) printk("In rs_wait_until_sent(%d) check=%lu...", timeout, char_time);
+	if (tty->driver.type != TTY_DRIVER_TYPE_PTY) printk("jiff=%lu...", jiffies);
 #endif
 	while (!((lsr = serial_inp(info, UART_LSR)) & UART_LSR_TEMT)) {
 #ifdef SERIAL_DEBUG_RS_WAIT_UNTIL_SENT
-		printk("lsr = %d (jiff=%lu)...", lsr, jiffies);
+		if (tty->driver.type != TTY_DRIVER_TYPE_PTY) printk("lsr = %d (jiff=%lu)...", lsr, jiffies);
 #endif
 		set_current_state(TASK_INTERRUPTIBLE);
 		schedule_timeout(char_time);
@@ -2957,7 +2961,7 @@ static void rs_wait_until_sent(struct tt
 			break;
 	}
 #ifdef SERIAL_DEBUG_RS_WAIT_UNTIL_SENT
-	printk("lsr = %d (jiff=%lu)...done\n", lsr, jiffies);
+	if (tty->driver.type != TTY_DRIVER_TYPE_PTY) printk("lsr = %d (jiff=%lu)...done\n", lsr, jiffies);
 #endif
 }
 
diff -rup --exclude '*SCCS*' --exclude BitKeeper linux.orig/drivers/char/tty_ioctl.c linux/drivers/char/tty_ioctl.c
--- linux.orig/drivers/char/tty_ioctl.c	Wed Mar  9 17:47:18 2005
+++ linux/drivers/char/tty_ioctl.c	Thu Mar 17 12:04:56 2005
@@ -25,7 +25,21 @@
 #include <asm/uaccess.h>
 #include <asm/system.h>
 
-#undef TTY_DEBUG_WAIT_UNTIL_SENT
+char dbg_msgbuf[1024*256] = { '\0' };
+char *dbg_msgcur = dbg_msgbuf;
+void dbg_addmsg(char *fmt, ...) {
+    va_list args;
+    va_start(args, fmt);
+    dbg_msgcur += vsprintf(dbg_msgcur, fmt, args);
+    va_end(args);
+    if (dbg_msgcur >= (dbg_msgbuf + sizeof(dbg_msgbuf))) {
+	panic("debug message buffer overflow");
+    }
+}
+
+
+#define TTY_DEBUG_WAIT_UNTIL_SENT
+#define printk(...) dbg_addmsg(__VA_ARGS__)
 
 #undef	DEBUG
 
@@ -43,7 +57,7 @@ void tty_wait_until_sent(struct tty_stru
 #ifdef TTY_DEBUG_WAIT_UNTIL_SENT
 	char buf[64];
 	
-	printk(KERN_DEBUG "%s wait until sent...\n", tty_name(tty, buf));
+	if (tty->driver.type != TTY_DRIVER_TYPE_PTY) printk(KERN_DEBUG "%s wait until sent...\n", tty_name(tty, buf));
 #endif
 	if (!tty->driver.chars_in_buffer)
 		return;
@@ -52,16 +66,21 @@ void tty_wait_until_sent(struct tty_stru
 		timeout = MAX_SCHEDULE_TIMEOUT;
 	do {
 #ifdef TTY_DEBUG_WAIT_UNTIL_SENT
-		printk(KERN_DEBUG "waiting %s...(%d)\n", tty_name(tty, buf),
+		if (tty->driver.type != TTY_DRIVER_TYPE_PTY) printk(KERN_DEBUG "waiting %s...(%d)\n", tty_name(tty, buf),
 		       tty->driver.chars_in_buffer(tty));
 #endif
 		set_current_state(TASK_INTERRUPTIBLE);
-		if (signal_pending(current))
+		if (signal_pending(current)) {
+			if (tty->driver.type != TTY_DRIVER_TYPE_PTY) printk(KERN_DEBUG "waiting on %s interrupted\n", tty_name(tty, buf));
 			goto stop_waiting;
+		}
 		if (!tty->driver.chars_in_buffer(tty))
 			break;
 		timeout = schedule_timeout(timeout);
 	} while (timeout);
+#ifdef TTY_DEBUG_WAIT_UNTIL_SENT
+	if (tty->driver.type != TTY_DRIVER_TYPE_PTY) printk("done waiting %s...(%d)\n", tty_name(tty, buf), tty->driver.chars_in_buffer(tty));
+#endif
 	if (tty->driver.wait_until_sent)
 		tty->driver.wait_until_sent(tty, timeout);
 stop_waiting: