From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alan Cox Subject: Re: [PATCH] via82cxxx IDE: Support multiple controllers Date: Thu, 13 Oct 2005 12:45:17 +0100 Message-ID: <1129203917.18635.1.camel@localhost.localdomain> References: <43146CC3.4010005@gentoo.org> <58cb370e05083008121f2eb783@mail.gmail.com> <43179CC9.8090608@gentoo.org> <58cb370e050927062049be32f8@mail.gmail.com> <434D2DF1.9070709@gentoo.org> <434D3266.9000203@gentoo.org> <1129139563.7966.4.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: Received: from clock-tower.bc.nu ([81.2.110.250]:60800 "EHLO lxorguk.ukuu.org.uk") by vger.kernel.org with ESMTP id S1750925AbVJMLQb (ORCPT ); Thu, 13 Oct 2005 07:16:31 -0400 In-Reply-To: <1129139563.7966.4.camel@localhost.localdomain> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Daniel Drake Cc: Bartlomiej Zolnierkiewicz , jgarzik@pobox.com, linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org, posting@blx4.net, vsu@altlinux.ru On Mer, 2005-10-12 at 18:52 +0100, Alan Cox wrote: > On Mer, 2005-10-12 at 16:57 +0100, Daniel Drake wrote: > > Uh, looks like the kernel just assumes 33mhz unless overriden by the user. Is > > this assumption generally accurate? > > If it is not, then there's probably no point displaying timing info... > > A small number of 486 systems use 25Mhz, some boards allow overclock at > 37.5Mhz on the PCI. I've been looking at this the past couple of days > for the libata via driver which I've been porting over and unfortunately > having been through the Northbridge manuals I can find no way to ask the > chipset what the PCI clock is set too. Ok I found what seems to be a pattern for the early chipsets with 25MHz support. If the bus speed of your 486 is 25Mhz the chipset is at 25MHz as is your IDE (ie 486/25, DX2/50, 3/75 - not sure about 4/100 etc). Now does anyone know how you find out if the CPU is 25MHz bus clocked on a 486 8)