From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752879AbZI1Tbb (ORCPT ); Mon, 28 Sep 2009 15:31:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752693AbZI1Tba (ORCPT ); Mon, 28 Sep 2009 15:31:30 -0400 Received: from mail.gmx.net ([213.165.64.20]:49092 "HELO mail.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1752358AbZI1Tba (ORCPT ); Mon, 28 Sep 2009 15:31:30 -0400 X-Authenticated: #272795 X-Provags-ID: V01U2FsdGVkX1/hdwtv5ErhIz26/jv+th4PrE/5v0DVCPbMTAEUpI qJs/5XS5mypOK3 Subject: Disabling DMA with ICH10? From: Lennart Baruschka Reply-To: FunFlyer@gmx.net To: linux-kernel@vger.kernel.org Content-Type: text/plain Date: Mon, 28 Sep 2009 23:31:21 +0200 Message-Id: <1254173481.4454.32.camel@goodbyte.homelinux.com> Mime-Version: 1.0 X-Mailer: Evolution 2.26.3 Content-Transfer-Encoding: 7bit X-Y-GMX-Trusted: 0 X-FuHaFi: 0.63 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, I'm new to this list, so please forgive me if this is the wrong place to ask. I'm trying to build a 2.6.30.5 kernel causing as little DMA traffic as possible in order to reduce latencies on a real-time system (using RTAI). 1. Is there a way to completely disable DMA usage system-wide? If not: 2. My system uses an ICH10 chipset, the harddrive is connected to the Intel SATA controller. Is there a way to disable DMA and switch back to PIO? I tried compiling with libata support and without SCSI support, but the kernel is unable to mount root (no matter if /dev/sda1 or /dev/hda1), then. 3. Another source seems to be the ATL1E driver for ethernet. Is it possible to either disable DMA for this? If disabling DMA is impossible for some reason for one or both drivers, is it at least possible to reduce the burst sizes so the bus gets free for a short time during which I could access it from my real time kernel module? Please point me in the right direction; any suggestion will be greatly appreciated! Cheers, Lennart