From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tim Small Subject: Re: ICH10 not working with AHCI kernel option Date: Fri, 09 Apr 2010 11:12:49 +0100 Message-ID: <4BBEFDA1.5050607@buttersideup.com> References: <4bbdde49.e302be0a.3106.0220@mx.google.com> <20100408145916.50dbe8de@lxorguk.ukuu.org.uk> <4bbde1ea.c701be0a.60ec.0270@mx.google.com> <20100408150920.5689564b@lxorguk.ukuu.org.uk> <4bbde4f7.1702be0a.5f6c.028e@mx.google.com> <4BBE6CA6.1010808@gmail.com> <4bbe8a6a.8602be0a.7951.0fb8@mx.google.com> <4bbe8f84.1502be0a.0f89.0f16@mx.google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from relay1.allsecurenet.com ([63.246.152.102]:39596 "EHLO relay1.allsecurenet.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757504Ab0DIKM4 (ORCPT ); Fri, 9 Apr 2010 06:12:56 -0400 In-Reply-To: Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Robert Hancock Cc: =?ISO-8859-1?Q?D=E2niel_Fraga?= , Alan Cox , linux-ide@vger.kernel.org Robert Hancock wrote: > We can detect an AHCI-capable Intel chipsets (in most cases anyway), > but problem is that a lot of systems with such chipsets, especially > laptops, unfortunately have no way to actually put the controller into > AHCI mode (no BIOS option for it). We could whine about it, but in a > lot of cases there's not much that can be done about it.. > I have a couple of machines with those BIOSes, and apart from the fact that the Intel ICH datasheets say something like "none but the saintly BIOS writers shall program this register", it does seem to be possible to put an ICH9R into AHCI mode using setpci and the fake hot plug driver... I just wondered what the potential pitfalls might be of doing this? Obviously you wouldn't want to be doing anything with the controller at the time that you change it's mode. Is there also the risk of the bloody bios fiddling with the device after the OS has booted (and then getting surprised about it no longer being in piix mode)? Cheers, Tim.