From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alan Cox Subject: Re: Questions regarding adding a patch in linux/drivers/char/8250.c Date: Mon, 21 May 2012 10:30:09 +0100 Message-ID: <20120521103009.7f4be5e0@pyramind.ukuu.org.uk> References: <00a301cd3719$b3faa370$1befea50$@com.tw> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Received: from lxorguk.ukuu.org.uk ([81.2.110.251]:52975 "EHLO lxorguk.ukuu.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932141Ab2EUJ1Q (ORCPT ); Mon, 21 May 2012 05:27:16 -0400 In-Reply-To: <00a301cd3719$b3faa370$1befea50$@com.tw> Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: Donald Cc: linux-serial@vger.kernel.org On Mon, 21 May 2012 14:19:34 +0800 "Donald" wrote: > Hi, > > This is Donald from ASIX Electronics Corp. My company has three PCI to Serial controllers, including MCS9845, MCS9835, and MCS9820. > Currently those serial devices using these three chips can directly use the Linux kernel's serial driver in > linux/drivers/char/8250.c. Recently we find these three chips have a hardware bug relating to parity error count function. We have a > software workaround for this issue. Below for reference is a pseudo code for this workaround. Actually I have a second question. Would it not be better to set the device to 8N1 and do the parity in software rather than lose the FIFO, especially at higher speeds ? Can you clarify what the erratum is triggered by ? Alan