Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750756AbVL2PXE (ORCPT ); Thu, 29 Dec 2005 10:23:04 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750759AbVL2PXE (ORCPT ); Thu, 29 Dec 2005 10:23:04 -0500 Received: from adsl-70-250-156-241.dsl.austtx.swbell.net ([70.250.156.241]:49338 "EHLO gw.microgate.com") by vger.kernel.org with ESMTP id S1750756AbVL2PXC (ORCPT ); Thu, 29 Dec 2005 10:23:02 -0500 Message-ID: <43B3FF55.4050304@microgate.com> Date: Thu, 29 Dec 2005 09:23:01 -0600 From: Paul Fulghum User-Agent: Mozilla Thunderbird 1.0 (Windows/20041206) X-Accept-Language: en-us, en MIME-Version: 1.0 To: =?ISO-8859-1?Q?Burkhard_Sch=F6lpen?= CC: linux-kernel@vger.kernel.org Subject: Re: PCI DMA burst delay References: <395333712@web.de> In-Reply-To: <395333712@web.de> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 804 Lines: 23 Burkhard Sch?lpen wrote: > ... in the (rarely) faulty case, the 2nd burst only starts > after another delay of about 600ns, which is too late Looking at the PCI 2.3 specification, arbitration latency on the order of a microsecond or two does not seem excessive for a 33MHz bus. > ... I deactivated all other pci devices that could disturb the transfers? Are you accessing registers on your device during the DMA transfers? If so, the CPU is acting as a PCI master that could delay granting the bus to your device. -- Paul Fulghum Microgate Systems, Ltd. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/