diff --git a/drivers/s390/char/con3215.c b/drivers/s390/char/con3215.c
index 0e1f35c..3e5653c 100644
--- a/drivers/s390/char/con3215.c
+++ b/drivers/s390/char/con3215.c
@@ -982,15 +982,16 @@
 /*
  * Put character routine for 3215 ttys
  */
-static void
+static int
 tty3215_put_char(struct tty_struct *tty, unsigned char ch)
 {
 	struct raw3215_info *raw;
 
 	if (!tty)
-		return;
+		return 0;
 	raw = (struct raw3215_info *) tty->driver_data;
 	raw3215_putchar(raw, ch);
+	return 1;
 }
 
 static void
diff --git a/drivers/s390/char/sclp_tty.c b/drivers/s390/char/sclp_tty.c
index e3b3d39..40b1152 100644
--- a/drivers/s390/char/sclp_tty.c
+++ b/drivers/s390/char/sclp_tty.c
@@ -412,14 +412,14 @@
  * - including previous characters from sclp_tty_put_char() and strings from
  * sclp_write() without final '\n' - will be written.
  */
-static void
+static int
 sclp_tty_put_char(struct tty_struct *tty, unsigned char ch)
 {
 	sclp_tty_chars[sclp_tty_chars_count++] = ch;
 	if (ch == '\n' || sclp_tty_chars_count >= SCLP_TTY_BUF_SIZE) {
 		sclp_tty_write_string(sclp_tty_chars, sclp_tty_chars_count);
 		sclp_tty_chars_count = 0;
-	}
+	} return 1;
 }
 
 /*
diff --git a/drivers/s390/char/sclp_vt220.c b/drivers/s390/char/sclp_vt220.c
index ed50759..35707c0 100644
--- a/drivers/s390/char/sclp_vt220.c
+++ b/drivers/s390/char/sclp_vt220.c
@@ -524,11 +524,15 @@
  * NOTE: include/linux/tty_driver.h specifies that a character should be
  * ignored if there is no room in the queue. This driver implements a different
  * semantic in that it will block when there is no more room left.
+ *
+ * FIXME: putchar can currently be called from BH and other non blocking
+ * handlers so  this semantic isn't a good idea.
  */
-static void
+static int
 sclp_vt220_put_char(struct tty_struct *tty, unsigned char ch)
 {
 	__sclp_vt220_write(&ch, 1, 0, 0, 1);
+	return 1;
 }
 
 /*
diff --git a/drivers/s390/char/tty3270.c b/drivers/s390/char/tty3270.c
index 70b1980a..c1f2ade 100644
--- a/drivers/s390/char/tty3270.c
+++ b/drivers/s390/char/tty3270.c
@@ -965,7 +965,7 @@
  * Insert character into the screen at the current position with the
  * current color and highlight. This function does NOT do cursor movement.
  */
-static void
+static int
 tty3270_put_character(struct tty3270 *tp, char ch)
 {
 	struct tty3270_line *line;
@@ -986,6 +986,7 @@
 	cell->character = tp->view.ascebc[(unsigned int) ch];
 	cell->highlight = tp->highlight;
 	cell->f_color = tp->f_color;
+	return 1;
 }
 
 /*