Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266741AbUJIMRc (ORCPT ); Sat, 9 Oct 2004 08:17:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266748AbUJIMRc (ORCPT ); Sat, 9 Oct 2004 08:17:32 -0400 Received: from spc2-brig1-3-0-cust232.asfd.broadband.ntl.com ([82.1.142.232]:34474 "EHLO ppgpenguin.kenmoffat.uklinux.net") by vger.kernel.org with ESMTP id S266741AbUJIMRa convert rfc822-to-8bit (ORCPT ); Sat, 9 Oct 2004 08:17:30 -0400 Date: Sat, 9 Oct 2004 13:17:24 +0100 (BST) From: Ken Moffat To: Bartlomiej Zolnierkiewicz Cc: linux-kernel@vger.kernel.org Subject: Re: Problem with ide=nodma In-Reply-To: <58cb370e04100817508fe62d0@mail.gmail.com> Message-ID: References: <58cb370e04100817353254b8cd@mail.gmail.com> <58cb370e04100817508fe62d0@mail.gmail.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=ISO-8859-15 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1245 Lines: 34 On Sat, 9 Oct 2004, Bartlomiej Zolnierkiewicz wrote: > > > Is it possible that you are reading it wrong? > > > > I don't think so, and the box is a lot more responsive. dmesg shows > > > > ide_setup: ide=nodmaIDE: Prevented DMA > > This is misleading as drivers are free to override this setting. > Bart, thanks for putting me straight. Indeed, siimage.c doesn't have 'if (!autodma)' to wrap 'hwif->autodma = 1;' like some of the others (e.g. hpt366). Easy enough for me to add it, but for reasons I'm too dumb to understand that turns off dma even without ide=nodma in the bootargs, and it then does a series of time out / resets if I try to enable dma with hdparm :-( Obviously, the sensible thing for me to do is to not touch siimage.c and to turn dma off with hdparm until I'm ready to do extended dma tests. It's not as if any sane platforms really want to add extra ide controllers and then cripple them. Thanks anyway. Ken -- das eine Mal als Trag?die, das andere Mal als Farce - 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/