3 files changed, 4 insertions, 4 deletions

diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index 5b15d9d8896b..e1f89416ef8c 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -750,7 +750,7 @@ static int acm_tty_chars_in_buffer(struct tty_struct *tty)
 {
         struct acm *acm = tty->driver_data;
         if (!ACM_READY(acm))
-                return -EINVAL;
+                return 0;
         /*
          * This is inaccurate (overcounts), but it works.
          */
diff --git a/drivers/usb/serial/mos7720.c b/drivers/usb/serial/mos7720.c
index bfc5ce000ef9..ccd4dd340d2c 100644
--- a/drivers/usb/serial/mos7720.c
+++ b/drivers/usb/serial/mos7720.c
@@ -521,7 +521,7 @@ static int mos7720_chars_in_buffer(struct tty_struct *tty)
         mos7720_port = usb_get_serial_port_data(port);
         if (mos7720_port == NULL) {
                 dbg("%s:leaving ...........", __func__);
-                return -ENODEV;
+                return 0;
         }
 
         for (i = 0; i < NUM_URBS; ++i) {
diff --git a/drivers/usb/serial/ti_usb_3410_5052.c b/drivers/usb/serial/ti_usb_3410_5052.c
index 14971a926990..3bc609fe2242 100644
--- a/drivers/usb/serial/ti_usb_3410_5052.c
+++ b/drivers/usb/serial/ti_usb_3410_5052.c
@@ -727,7 +727,7 @@ static int ti_write_room(struct tty_struct *tty)
         dbg("%s - port %d", __func__, port->number);
 
         if (tport == NULL)
-                return -ENODEV;
+                return 0;
 
         spin_lock_irqsave(&tport->tp_lock, flags);
         room = ti_buf_space_avail(tport->tp_write_buf);
@@ -748,7 +748,7 @@ static int ti_chars_in_buffer(struct tty_struct *tty)
         dbg("%s - port %d", __func__, port->number);
 
         if (tport == NULL)
-                return -ENODEV;
+                return 0;
 
         spin_lock_irqsave(&tport->tp_lock, flags);
         chars = ti_buf_data_avail(tport->tp_write_buf);