diff --git a/drivers/isdn/i4l/isdn_tty.c b/drivers/isdn/i4l/isdn_tty.c
index 9cb6e5021adb..133eb18e65cc 100644
--- a/drivers/isdn/i4l/isdn_tty.c
+++ b/drivers/isdn/i4l/isdn_tty.c
@@ -1917,7 +1917,6 @@ isdn_tty_modem_init(void)
 		info->owner = THIS_MODULE;
 #endif
 		spin_lock_init(&info->readlock);
-		init_MUTEX(&info->write_sem);
 		sprintf(info->last_cause, "0000");
 		sprintf(info->last_num, "none");
 		info->last_dir = 0;
diff --git a/include/linux/isdn.h b/include/linux/isdn.h
index d0ecc8eebfbf..9cb2855bb170 100644
--- a/include/linux/isdn.h
+++ b/include/linux/isdn.h
@@ -507,7 +507,6 @@ typedef struct modem_info {
   struct ktermios	normal_termios;  /* For saving termios structs     */
   struct ktermios	callout_termios;
   wait_queue_head_t	open_wait, close_wait;
-  struct semaphore      write_sem;
   spinlock_t	        readlock;
 } modem_info;