From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg KH Subject: Re: serial/mxs-auart: Unable to get interrupt counter from user space Date: Sat, 23 Jun 2012 19:25:47 -0700 Message-ID: <20120624022547.GA7307@kroah.com> References: <4FE616CC.9000709@lategoodbye.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-pb0-f46.google.com ([209.85.160.46]:54932 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753130Ab2FXCZx (ORCPT ); Sat, 23 Jun 2012 22:25:53 -0400 Received: by pbbrp8 with SMTP id rp8so5109109pbb.19 for ; Sat, 23 Jun 2012 19:25:52 -0700 (PDT) Content-Disposition: inline In-Reply-To: <4FE616CC.9000709@lategoodbye.de> Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: Stefan Wahren Cc: linux-serial@vger.kernel.org On Sat, Jun 23, 2012 at 09:19:40PM +0200, Stefan Wahren wrote: > Hello, > > i'm using Linux 2.6.35 at ARM and i experience the following issue > with the mxs-auart (App UART). If i transmit and receive data over > the serial port (using mxs-auart), all the interrupt counter (RX, > TX, frame, parity, break) accessed from user space (ioctl with > TIOCGICOUNT or /proc/tty/driver/auart) are zero. > > Here is the scenario to reproduce the problem: > > 1. echoing some characters to the uart device > 2. fetch the statistics from proc-Filesystem > > Expected results: transmit counter greater than zero > > Observed results: transmit counter is always zero > > The same szenario on the mxs-duart (Debug UART) doesn't show this problem. > > Is this a bug in mxs-auart or just not implemented? We disabled the transmit counter from being displayed a while ago for security reasons, perhaps that is what you are seeing? Also, you do realize just how old 2.6.35 really is, right? thanks, greg k-h