From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D5F2B31F9A4; Mon, 31 Aug 2026 03:07:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788145670; cv=none; b=RUGM7ztF4WI6gpkM1AbmkodjT7FT1M2pH1v+obBkn+WRJno8X34AwvXA8lRfGjXytXRfPgsrFpEs8l6TzK87CYF0BzBtnIBBfs3qHIAPElDWZe+cNtVakCDgMv/j9Y+2nxDmTNkLrxoXhE5jmMpvCp8UTRPcp9ZX8hxN53KbGN0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788145670; c=relaxed/simple; bh=gLr+Iwb+ZCQmXvh641mg06UhyG3OYgUsPvWbmyuhsq4=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=LajmICAYi4XjIct4ObiolRMQXjDeSOoH+du3XsWoRxcnjcllLpsYXDHGUY/hdPAPK3+3wRTmk2DOgxhk66UT4BewwvQrRLE9kohpkk8aXquPpAWvtd44uNVemY+vYT6jezooV8OfUG/T8Re9JSpkSqE7eHgp2v9I0UtAuKzQxlM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=HeEmWeHY; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="HeEmWeHY" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2334A1F000E9; Mon, 31 Aug 2026 03:07:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788145669; bh=3PBI0fUvzmz9NLpVR+qeiZpMag6fP4x3JVvKUNI8hvI=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=HeEmWeHY82ZIX6dLS7QxC6izKBTZloyocSHkK1Sh4VXrx9UJGXxyXJYtokn/Wjj6G 6RaypVC7JMGQSVqpHv1qMTeMeFRMyBOoSZvZLRsTosuIIJV2Rc965PY8tUxn/Nos5O 1KKOeM407KJBNwGjzxv4nXYqslwdV88/UCyRcQm8cD57L/FsS6WbcVSYjYknR9UaS/ H3H+3PoMTjHkZOL73lFHaEh+D5biSNnY5gMqI8q/0W9dLJ7yjV8+qaj5skN8dQUCJ6 Ehq2AWxp0vf8goZ2PqoRk50Y7eZkkhulzy1IujxurOx993ACKUUsnPdcGaG94Bjhul M38pJvVTkrK9w== Message-ID: <8f39c9fd-cc6e-42cf-9761-ae1922898d4a@kernel.org> Date: Mon, 31 Aug 2026 05:07:46 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 2/2] serial: 8250_mid: wait for LSR tx empty before setting termios To: Tate Whiteberg , Andy Shevchenko Cc: Greg Kroah-Hartman , Andy Shevchenko , linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org References: <20260828175733.1650267-1-whiteberg@arista.com> <20260828175733.1650267-3-whiteberg@arista.com> Content-Language: en-US From: Jiri Slaby Autocrypt: addr=jirislaby@kernel.org; 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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 28. 08. 26, 19:57, Tate Whiteberg wrote: > If mid8250_set_termios() is called while data is still in transmission, > the corresponding register updates will corrupt the transmission. > > Fix this by locking the port and and waiting for the transmitter to > empty before performing updates. It is necessary to wait for both > UART_LSR_THRE and UART_LSR_TEMT to ensure the final character is sent. > > Fixes: d9eda9bab237 ("serial: 8250_pci: Intel MID UART support to its own driver") > Signed-off-by: Tate Whiteberg > --- > Changes in v2: > - Separate changes to 8250.h and 8250_port.c into prerequisite patch, > as recommended by andriy.shevchenko@intel.com > - Apply feedback from andriy.shevchenko@intel.com to 8250_mid.c > > drivers/tty/serial/8250/8250_mid.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/drivers/tty/serial/8250/8250_mid.c b/drivers/tty/serial/8250/8250_mid.c > index 82656645b8a6..ce792888acfe 100644 > --- a/drivers/tty/serial/8250/8250_mid.c > +++ b/drivers/tty/serial/8250/8250_mid.c > @@ -209,6 +209,7 @@ static void mid8250_set_termios(struct uart_port *p, struct ktermios *termios, > const struct ktermios *old) > { > unsigned int baud = tty_termios_baud_rate(termios); > + struct uart_8250_port *up = up_to_u8250p(p); > struct mid8250 *mid = p->private_data; > unsigned short ps = 16; > unsigned long fuart = baud * ps; > @@ -231,12 +232,18 @@ static void mid8250_set_termios(struct uart_port *p, struct ktermios *termios, > } > > rational_best_approximation(fuart, mid->board->freq, w, w, &mul, &div); > + > + uart_port_lock_irq(p); Use scoped_guard(), please. -- js suse labs