From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750715AbWDSCoO (ORCPT ); Tue, 18 Apr 2006 22:44:14 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750722AbWDSCoO (ORCPT ); Tue, 18 Apr 2006 22:44:14 -0400 Received: from shawidc-mo1.cg.shawcable.net ([24.71.223.10]:4958 "EHLO pd2mo1so.prod.shaw.ca") by vger.kernel.org with ESMTP id S1750715AbWDSCoN (ORCPT ); Tue, 18 Apr 2006 22:44:13 -0400 Date: Tue, 18 Apr 2006 20:44:03 -0600 From: Robert Hancock Subject: Re: [PATCH 1/1] ide: Allow disabling of UDMA for Compact Flash devices In-reply-to: <631pe-5Gt-7@gated-at.bofh.it> To: linux-kernel Cc: James Ausmus Message-id: <4445A3F3.6050907@shaw.ca> MIME-version: 1.0 Content-type: text/plain; charset=ISO-8859-1; format=flowed Content-transfer-encoding: 7bit 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> User-Agent: Thunderbird 1.5 (Windows/20051201) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org 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)? -- Robert Hancock Saskatoon, SK, Canada To email, remove "nospam" from hancockr@nospamshaw.ca Home Page: http://www.roberthancock.com/