From: Johan Hovold <johan@kernel.org>
To: linux-usb@vger.kernel.org
Cc: Sheng Long Wang <shenglong.wang.ext@siemens.com>,
linux-kernel@vger.kernel.org, Johan Hovold <johan@kernel.org>
Subject: [PATCH 1/6] USB: serial: cp210x: return early on unchanged termios
Date: Mon, 16 Nov 2020 17:18:21 +0100 [thread overview]
Message-ID: <20201116161826.29417-2-johan@kernel.org> (raw)
In-Reply-To: <20201116161826.29417-1-johan@kernel.org>
Return early from set_termios() in case no relevant terminal settings
have changed.
This avoids testing each parameter in turn and specifically allows the
line-control handling to be cleaned up further.
Signed-off-by: Johan Hovold <johan@kernel.org>
---
drivers/usb/serial/cp210x.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
index d0c05aa8a0d6..f1fd109d97d5 100644
--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
@@ -1352,6 +1352,15 @@ static void cp210x_disable_event_mode(struct usb_serial_port *port)
port_priv->event_mode = false;
}
+static bool cp210x_termios_change(const struct ktermios *a, const struct ktermios *b)
+{
+ bool iflag_change;
+
+ iflag_change = ((a->c_iflag ^ b->c_iflag) & INPCK);
+
+ return tty_termios_hw_change(a, b) || iflag_change;
+}
+
static void cp210x_set_termios(struct tty_struct *tty,
struct usb_serial_port *port, struct ktermios *old_termios)
{
@@ -1359,6 +1368,9 @@ static void cp210x_set_termios(struct tty_struct *tty,
unsigned int cflag, old_cflag;
u16 bits;
+ if (!cp210x_termios_change(&tty->termios, old_termios))
+ return;
+
cflag = tty->termios.c_cflag;
old_cflag = old_termios->c_cflag;
--
2.26.2
next prev parent reply other threads:[~2020-11-16 16:18 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-16 16:18 [PATCH 0/6] USB: serial: cp210x: clean up termios handling Johan Hovold
2020-11-16 16:18 ` Johan Hovold [this message]
2020-11-16 16:18 ` [PATCH 2/6] USB: serial: cp210x: clean up line-control handling Johan Hovold
2020-11-16 16:18 ` [PATCH 3/6] USB: serial: cp210x: set terminal settings on open Johan Hovold
2020-11-16 16:18 ` [PATCH 4/6] USB: serial: cp210x: drop flow-control debugging Johan Hovold
2020-11-16 16:18 ` [PATCH 5/6] USB: serial: cp210x: refactor flow-control handling Johan Hovold
2020-11-16 16:18 ` [PATCH 6/6] USB: serial: cp210x: clean up dts_rts Johan Hovold
2020-12-04 13:59 ` [PATCH 0/6] USB: serial: cp210x: clean up termios handling Johan Hovold
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