From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg KH Subject: Re: [PPC/MPC5200B] strange data loss on uart reception Date: Sun, 31 Oct 2010 20:10:03 -0700 Message-ID: <20101101031003.GA2903@kroah.com> References: <1288546021.1866.1@antares> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from kroah.org ([198.145.64.141]:44873 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755272Ab0KADKl (ORCPT ); Sun, 31 Oct 2010 23:10:41 -0400 Content-Disposition: inline In-Reply-To: <1288546021.1866.1@antares> Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: Albrecht Dre? Cc: linux-serial@vger.kernel.org On Sun, Oct 31, 2010 at 06:27:00PM +0100, Albrecht Dre? wrote: Am I simply too dumb to use the uart correctly, or is there some issue > in the kernel causing this effect? I noticed that the function > mpc52xx_uart_int_rx_chars() does not check the return value of > tty_insert_flip_char(). If the system runs out of space (actually, > the maximum buffer size used should be limited, in particular on > embedded systems!), might this go undetected? This might explain the > bigger "chunks", as the '5200's uart has a rather big fifo (512 > bytes). That might help, have you tried changing this and seeing if it fixes anything? Also, are you sure your userspace application is checking the return value of write() to verify that it really wrote everything it thought it did? thanks, greg k-h