From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Aubrey Li" Subject: [BUG]: 2.6.19.2: Weird serial core issue Date: Wed, 31 Jan 2007 18:49:25 +0800 Message-ID: <6d6a94c50701310249o2b2c8024i4d3f28ec1601246a@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from wx-out-0506.google.com ([66.249.82.231]:22323 "EHLO wx-out-0506.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932996AbXAaKt0 (ORCPT ); Wed, 31 Jan 2007 05:49:26 -0500 Received: by wx-out-0506.google.com with SMTP id h31so169336wxd for ; Wed, 31 Jan 2007 02:49:25 -0800 (PST) Content-Disposition: inline Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: linux-kernel@vger.kernel.org Cc: linux-serial@vger.kernel.org I insert one printk into drivers/serial/serial_core.c: uart_set_termios() to describe the issue. static void uart_set_termios(struct tty_struct *tty, struct termios *old_termios) { ----snip---- unsigned int cflag = tty->termios->c_cflag; BUG_ON(!kernel_locked()); +++printk("new_termios flag: 0x%x, old_termios flag: 0x%x\n"); +++ cflag, old_termios->c_cflag); ----snip ---- } When I telnet my board and run the following command: ---- root:~> stty -F /dev/ttyS0 -crtscts I got the following result from the console of my board: ---- root:~>new_termios flag: 0x1cb1, old_termios flag: 0x80001cb1 That's correct. CRTSCTS flag is clear But when I type "ENTER" key on the console, I got: ----root:~>new_termios flag: 0x80001cb1, old_termios flag: 0x1cb1 The CRTSCTS flag is set back. But I didn't set it back, I just type "ENTER". I guess, Is it a serial core bug? -Aubrey