Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753241AbZI1Uhf (ORCPT ); Mon, 28 Sep 2009 16:37:35 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753226AbZI1Uhe (ORCPT ); Mon, 28 Sep 2009 16:37:34 -0400 Received: from ey-out-2122.google.com ([74.125.78.24]:19153 "EHLO ey-out-2122.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753230AbZI1Uhd convert rfc822-to-8bit (ORCPT ); Mon, 28 Sep 2009 16:37:33 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:in-reply-to:references:x-mailer :mime-version:content-type:content-transfer-encoding; b=r939g6nXSIX0oMJVn5RpiJU0A5xALpFN7oILdytCpZNewWOAstcmIElrPQMZOAx1NY 1WA5UchRRfuwi8pPgI73CLO1dpKj1uRo81wlSdMRFtuvZ6TrCr2n5Wtk0aZ/aWLzPYsa esBNpJyaUyl3HPiCDhO6la1CGFhtV2NcvV1eU= Date: Mon, 28 Sep 2009 22:37:27 +0200 From: Alejandro Riveira =?UTF-8?B?RmVybsOhbmRleg==?= To: FunFlyer@gmx.net Cc: linux-kernel@vger.kernel.org Subject: Re: Disabling DMA with ICH10? Message-ID: <20090928223727.0b1367b7@varda> In-Reply-To: <1254173481.4454.32.camel@goodbyte.homelinux.com> References: <1254173481.4454.32.camel@goodbyte.homelinux.com> X-Mailer: Claws Mail 3.7.2 (GTK+ 2.16.1; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1600 Lines: 48 El Mon, 28 Sep 2009 23:31:21 +0200 Lennart Baruschka escribió: > 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. AFAIK libata needs scsi support. To disable dma in libata I get from Documentation/kernel-parameters.txt --> libata.dma = 0 > 3. Another source seems to be the ATL1E driver for ethernet. Is it > possible to either disable DMA for this? That I dunno > > 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 Saludos, Alejandro -- 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/