This is required, otherwise a user will get a EINVAL while opening a non-existing device, instead of ENODEV. This is what I get with this patch applied now instead of an "Invalid argument". cascardo@vespa:~$ cat /dev/ttyACM0 cat: /dev/ttyACM0: No such device cascardo@vespa:~$ Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@xxxxxxxxxxxxxx> --- drivers/usb/class/cdc-acm.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c index 38bfdb0..02eb60b 100644 --- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -550,7 +550,7 @@ static void acm_waker(struct work_struct *waker) static int acm_tty_open(struct tty_struct *tty, struct file *filp) { struct acm *acm; - int rv = -EINVAL; + int rv = -ENODEV; int i; dbg("Entering acm_tty_open."); -- 1.6.3 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html