From owner-freebsd-questions Thu Apr 12 20:46:11 2001 Delivered-To: freebsd-questions@freebsd.org Received: from mail.gmx.net (pop.gmx.net [194.221.183.20]) by hub.freebsd.org (Postfix) with SMTP id D301D37B506 for ; Thu, 12 Apr 2001 20:46:07 -0700 (PDT) (envelope-from michaelnottebrock@gmx.net) Received: (qmail 11626 invoked by uid 0); 13 Apr 2001 03:46:05 -0000 Received: from pd4b9eee4.dip.t-dialin.net (HELO lofizwei) (212.185.238.228) by mail.gmx.net (mail01) with SMTP; 13 Apr 2001 03:46:05 -0000 Message-ID: <012701c0c3cc$a952e260$0508a8c0@lofi.dyndns.org> From: "Michael Nottebrock" To: "brian j. peterson" , References: Subject: Re: turning off DMA pre-boot Date: Fri, 13 Apr 2001 05:48:49 +0200 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.50.4522.1200 X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4522.1200 Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG ----- Original Message ----- From: "brian j. peterson" To: Sent: Wednesday, April 11, 2001 11:11 PM Subject: turning off DMA pre-boot > background: > > i have a 4.3-BETA system that is freezing on me every few days. (the > cvsup from 4.2-R to stable was done around March 11th.) i have trimmed > down the kernel as much as possible in an attempt to isolate the problem, > but this hasn't helped so far. the motherboard this system is on uses a > VIA chipset, and i have been hearing that VIA's DMA support is less than > perfect. turning off DMA in the BIOS didn't seem to stop FreeBSD from > using DMA (at least according to 'sysctl hw.atamodes'). i was able to > turn off DMA _after_ boot by running 'sysctl -w hw.atamodes=pio,pio,'. (i > just did this last night, so i'm not sure if this has solved the system's > freezing problem.) > > question: > > is there some way to disable DMA support (and force PIO mode) before the > system boots? perhaps a kernel option or a loader option? > > any help would be greatly appreciated. > > thanks for your time, > brian There is, at least in the latest 4.3's. You can set hw.ata.ata_dma="0" in /boot/loader.conf amongst some other options. Turning off dma after booting should have solved your problem, though, if it was really ide-dma related. Also see 'man ata' for details. Greetings, Michael Nottebrock To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message