From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261186AbTJCUcB (ORCPT ); Fri, 3 Oct 2003 16:32:01 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261200AbTJCUcB (ORCPT ); Fri, 3 Oct 2003 16:32:01 -0400 Received: from mion.elka.pw.edu.pl ([194.29.160.35]:39599 "EHLO mion.elka.pw.edu.pl") by vger.kernel.org with ESMTP id S261186AbTJCUb7 (ORCPT ); Fri, 3 Oct 2003 16:31:59 -0400 From: Bartlomiej Zolnierkiewicz To: Allen Martin , Vojtech Pavlik Subject: Re: [PATCH][IDE] small cleanup for AMD/nVidia IDE driver Date: Fri, 3 Oct 2003 22:35:14 +0200 User-Agent: KMail/1.5.4 Cc: linux-kernel@vger.kernel.org References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-2" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200310032235.14733.bzolnier@elka.pw.edu.pl> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Friday 03 of October 2003 21:51, Allen Martin wrote: > > I've seen 2.4.x patches from Allen Martin@nVidia on lkml. > > In UDMA133 patch he mentioned that UDMA should be programmed by mode, > > not UDMA cycle timing on nVidia chipsets (probably the same > > applies to AMD). > > Can you comment on this? > > Yes, these controllers have a 1:1 mapping between UDMA mode and > AMD_UDMA_TIMING value. Trying to map UDMA mode to cycle time and then map > back to UDMA mode is error prone, and cause for some of the ugly > workarounds in the current driver. My patch to add Ultra133 support just > expands this ugliness, but works. > > The mapping is as follows: > > UDMA2 0 > UDMA1 1 > UDMA0 2 > UDMA3 4 > UDMA4 5 > UDMA5 6 > UDMA6 7 Thanks for explaining this. Vojtech please consider it in your future patches. ;-) > Other ACPI aware OS'es use an ACPI method to change IDE timing, so this is > hidden from the OS. Damn, I must take a look at ACPI specification 8-). --bartlomiej