USB: fix cdc-acm regression in open

cdc-acm needs to set a flag during open to tell the
tty layer that the device is initialized

Signed-off-by: Oliver Neukum <oliver@neukum.org>
Cc: Marcel Holtmann <marcel@holtmann.org>
Cc: Paul Martin <pm@debian.org>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index 85a1a55815cf..e3861b21e776 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -59,6 +59,7 @@
 #include <linux/init.h>
 #include <linux/slab.h>
 #include <linux/tty.h>
+#include <linux/serial.h>
 #include <linux/tty_driver.h>
 #include <linux/tty_flip.h>
 #include <linux/module.h>
@@ -609,6 +610,7 @@ static int acm_tty_open(struct tty_struct *tty, struct file *filp)
         acm->throttle = 0;
 
         tasklet_schedule(&acm->urb_task);
+        set_bit(ASYNCB_INITIALIZED, &acm->port.flags);
         rv = tty_port_block_til_ready(&acm->port, tty, filp);
 done:
         mutex_unlock(&acm->mutex);