From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750907AbWDSPfv (ORCPT ); Wed, 19 Apr 2006 11:35:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750906AbWDSPfv (ORCPT ); Wed, 19 Apr 2006 11:35:51 -0400 Received: from xproxy.gmail.com ([66.249.82.198]:60689 "EHLO xproxy.gmail.com") by vger.kernel.org with ESMTP id S1750908AbWDSPfu convert rfc822-to-8bit (ORCPT ); Wed, 19 Apr 2006 11:35:50 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=o5gZeB6QiQt4acVe+PgU6hUKxHPvwoNaAauz4F/146OhUHBr5VQaZZATo2/ebqqLDppcCqsO7/uHOcKQN5vdBIBWpapCDyzjI5WpjLQ1HgyN+PaDElSt6BptMpV0ZZgasM5gku660ceM/ehXqVUapby+b4OyNOu9yJ6vO76oqNw= Message-ID: Date: Wed, 19 Apr 2006 08:35:22 -0700 From: "James Ausmus" To: "Robert Hancock" Subject: Re: [PATCH 1/1] ide: Allow disabling of UDMA for Compact Flash devices Cc: linux-kernel In-Reply-To: <4445A3F3.6050907@shaw.ca> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT Content-Disposition: inline References: <62LaJ-6vK-5@gated-at.bofh.it> <62Wg0-6f8-29@gated-at.bofh.it> <62WJ1-6Od-31@gated-at.bofh.it> <62WSE-70D-21@gated-at.bofh.it> <631pe-5Gt-7@gated-at.bofh.it> <4445A3F3.6050907@shaw.ca> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On 4/18/06, Robert Hancock wrote: > James Ausmus wrote: > > This is exactly the situation that I have with 2 separate "dumb" (just > > physical interfaces, essentially - not at all detectable) IDE->CF > > adapters - both the IDE controller and the CF media support several > > UDMA modes, so the IDE driver throws the CF device into UDMA mode on > > bootup. However, as the physical interface between the IDE cable and > > the CF socket is poorly engineered, it cannot handle the higher > > speeds, causing the timeout errors. For some people, this can just be > > fixed with an ide=nodma boot option, but as I also have a (quite > > large) rotating media device on the controller, this is not an option, > > as, if a fsck is performed on a boot, the boot-up time is upwards of > > 30 minutes. > > If it's like some of the CF-IDE adapters I've seen, the DMA request/ack > lines likely aren't even wired up between the card and the cable. > There's no way the kernel can detect that DMA is not actually possible > on such a card without trying and waiting for it to timeout. (I've seen > a few which have jumpers which select whether to connect these or not - > haven't a clue why you wouldn't want to hook those up unconditionally..) > > Isn't there an option to disable DMA for a specific IDE channel > (ide2=nodma or something like that)? > Yes, there is, but that unfortunately does not solve the issue for configurations where there is also a UDMA capable device on the same channel. If there was something like ide2=0:nodma,1:dma or some such, in order to enable/disable dma on a per device basis, instead of a per-channel basis, then that would also solve the issue. -James > -- > Robert Hancock Saskatoon, SK, Canada > To email, remove "nospam" from hancockr@nospamshaw.ca > Home Page: http://www.roberthancock.com/ > >