From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 4 Jun 2001 21:28:13 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 4 Jun 2001 21:28:03 -0400 Received: from horus.its.uow.edu.au ([130.130.68.25]:1723 "EHLO horus.its.uow.edu.au") by vger.kernel.org with ESMTP id ; Mon, 4 Jun 2001 21:27:53 -0400 Message-ID: <3B1C33C5.AB6C8CD0@uow.edu.au> Date: Tue, 05 Jun 2001 11:20:05 +1000 From: Andrew Morton X-Mailer: Mozilla 4.76 [en] (X11; U; Linux 2.4.5-pre4 i686) X-Accept-Language: en MIME-Version: 1.0 To: safemode CC: William Montgomery , Andrea Arcangeli , linux-kernel@vger.kernel.org Subject: Re: lowlatency 2.2.19 In-Reply-To: , <01060420580802.31206@psuedomode> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org safemode wrote: > > this is just a general question about low latency patches on 2.2, I > remember hearing about low latency patches for 2.4 not playing well with X > 4.x, is this true for 2.2 low latency patches as well? Yes, it would be the case. Some video cards have a PCI cheat-mode in which they keep the PCI bus busy until they are ready to accept new commands, rather forcing a retry. Figures of up to twenty milliseconds have been mentioned. Your X server *may* support the `PCIRetry' config option which will defeat this. Info: http://www.lib.uaa.alaska.edu/linux-kernel/archive/2001-Week-02/1566.html http://www.zefiro.com/vgakills.txt http://www.zdnet.com/pcmag/news/trends/t980619a.htm http://www.research.microsoft.com/~mbj/papers/tr-98-29.html -