From 4473d054ceb572557954f9536731d39b20937b0c Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Wed, 5 Nov 2014 18:41:59 +0100 Subject: [PATCH] USB: cdc-acm: only raise DTR on transitions from B0 Make sure to only raise DTR on transitions from B0 in set_termios. Also allow set_termios to be called from open with a termios_old of NULL. Note that DTR will not be raised prematurely in this case. Cc: stable Signed-off-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman --- drivers/usb/class/cdc-acm.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c index 6771f884cb82..9d6495424b06 100644 --- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -985,11 +985,12 @@ static void acm_tty_set_termios(struct tty_struct *tty, /* FIXME: Needs to clear unsupported bits in the termios */ acm->clocal = ((termios->c_cflag & CLOCAL) != 0); - if (!newline.dwDTERate) { + if (C_BAUD(tty) == B0) { newline.dwDTERate = acm->line.dwDTERate; newctrl &= ~ACM_CTRL_DTR; - } else + } else if (termios_old && (termios_old->c_cflag & CBAUD) == B0) { newctrl |= ACM_CTRL_DTR; + } if (newctrl != acm->ctrlout) acm_set_control(acm, acm->ctrlout = newctrl);