cdc-acm: fix power management in ioctl
An ioctl that does depends on communication with a device should
prevent suspension of teh device.
Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index 92e28ec..8fe32eb 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -888,7 +888,13 @@
rv = set_serial_info(acm, (struct serial_struct __user *) arg);
break;
case TIOCMIWAIT:
+ rv = usb_autopm_get_interface(acm->control);
+ if (rv < 0) {
+ rv = -EIO;
+ break;
+ }
rv = wait_serial_change(acm, arg);
+ usb_autopm_put_interface(acm->control);
break;
case TIOCGICOUNT:
rv = get_serial_usage(acm, (struct serial_icounter_struct __user *) arg);