Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936596AbdCJMMI (ORCPT ); Fri, 10 Mar 2017 07:12:08 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:45074 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S936434AbdCJMMF (ORCPT ); Fri, 10 Mar 2017 07:12:05 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Johan Hovold" Date: Fri, 10 Mar 2017 11:46:23 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 201/370] USB: serial: ch341: fix modem-control and B0 handling In-Reply-To: X-SA-Exim-Connect-IP: 82.70.136.246 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1925 Lines: 55 3.16.42-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Johan Hovold commit 030ee7ae52a46a2be52ccc8242c4a330aba8d38e upstream. The modem-control signals are managed by the tty-layer during open and should not be asserted prematurely when set_termios is called from driver open. Also make sure that the signals are asserted only when changing speed from B0. Fixes: 664d5df92e88 ("USB: usb-serial ch341: support for DTR/RTS/CTS") Signed-off-by: Johan Hovold Signed-off-by: Ben Hutchings --- drivers/usb/serial/ch341.c | 16 +++++++--------- 1 file changed, 7 insertions(+), 9 deletions(-) --- a/drivers/usb/serial/ch341.c +++ b/drivers/usb/serial/ch341.c @@ -357,10 +357,6 @@ static void ch341_set_termios(struct tty ctrl = CH341_LCR_ENABLE_RX | CH341_LCR_ENABLE_TX | CH341_LCR_CS8; if (baud_rate) { - spin_lock_irqsave(&priv->lock, flags); - priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS); - spin_unlock_irqrestore(&priv->lock, flags); - priv->baud_rate = baud_rate; r = ch341_init_set_baudrate(port->serial->dev, priv, ctrl); @@ -368,13 +364,14 @@ static void ch341_set_termios(struct tty priv->baud_rate = tty_termios_baud_rate(old_termios); tty_termios_copy_hw(&tty->termios, old_termios); } - } else { - spin_lock_irqsave(&priv->lock, flags); - priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS); - spin_unlock_irqrestore(&priv->lock, flags); } - ch341_set_handshake(port->serial->dev, priv->line_control); + spin_lock_irqsave(&priv->lock, flags); + if (C_BAUD(tty) == B0) + priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS); + else if (old_termios && (old_termios->c_cflag & CBAUD) == B0) + priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS); + spin_unlock_irqrestore(&priv->lock, flags); /* Unimplemented: * (cflag & CSIZE) : data bits [5, 8]