--- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -659,7 +659,8 @@ static void acm_port_dtr_rts(struct tty_ res = acm_set_control(acm, val); if (res && (acm->ctrl_caps & USB_CDC_CAP_LINE)) - dev_err(&acm->control->dev, "failed to set dtr/rts\n"); + /* This is broken in too many devices to spam the logs */ + dev_dbg(&acm->control->dev, "failed to set dtr/rts\n"); } static int acm_port_activate(struct tty_port *port, struct tty_struct *tty)