From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alan Cox Subject: Re: [PATCH] serial: 8250 check iir rdi in interrupt Date: Tue, 23 Oct 2012 11:01:33 +0100 Message-ID: <20121023110133.62bed522@pyramind.ukuu.org.uk> References: 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]:49934 "EHLO lxorguk.ukuu.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932503Ab2JWJ4a (ORCPT ); Tue, 23 Oct 2012 05:56:30 -0400 In-Reply-To: Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: Min Zhang Cc: gregkh@linuxfoundation.org, linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org > Added module parameter skip_rdi_check to opt out this workaround. NAK. Anything like this should be runtime. > Tested on Radisys ATCA 46XX which uses FPGA 16550-compatible and > other generic 16550 UART. It takes from an hour to days to reproduce by > pumping inputs to serial console continously using TeraTerm script: You turn this on by default but it's a nasty IRQ latency penalty on a lot of x86 platforms with the uarts on the lpc bus. What I am not clear on from this is - do you see it on both the ports (the bug that is) - if you do see it on both are you sure its not in reality a symptom of some other console/irq handling race ? Alan