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: Sun, 24 Jun 2012 10:53:07 -0700 Message-ID: <20120624175307.GB29455@kroah.com> References: <4FE616CC.9000709@lategoodbye.de> <20120624022547.GA7307@kroah.com> <4FE6DA89.50503@lategoodbye.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-pz0-f46.google.com ([209.85.210.46]:65199 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751545Ab2FXRxM (ORCPT ); Sun, 24 Jun 2012 13:53:12 -0400 Received: by dady13 with SMTP id y13so4362264dad.19 for ; Sun, 24 Jun 2012 10:53:11 -0700 (PDT) Content-Disposition: inline In-Reply-To: <4FE6DA89.50503@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 Sun, Jun 24, 2012 at 11:14:49AM +0200, Stefan Wahren wrote: > Hi, > > Am 24.06.2012 04:25, schrieb Greg KH: > >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? > > Does this security fix affect serial_core or only mxs-auart? I do not recall, sorry. > Prevent this security fix from reading all counter (TX, RX, frame > erros, parity errors, breaks)? > > Do you mean this security issue ( > https://bugzilla.redhat.com/show_bug.cgi?id=648660 ) ? Nope, a different one. > >Also, you do realize just how old 2.6.35 really is, right? > > Unfortunaley yes, Freescale the vendor delivers the Board Support > Package only with 2.6.35. I suggest you contact Freescale for support for this issue then, as there's nothing we can do about that old kernel version, sorry. good luck, greg k-h