From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754794AbZEYWfn (ORCPT ); Mon, 25 May 2009 18:35:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752778AbZEYWfg (ORCPT ); Mon, 25 May 2009 18:35:36 -0400 Received: from earthlight.etchedpixels.co.uk ([81.2.110.250]:48093 "EHLO www.etchedpixels.co.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752615AbZEYWff (ORCPT ); Mon, 25 May 2009 18:35:35 -0400 Date: Mon, 25 May 2009 23:36:43 +0100 From: Alan Cox To: Frans Pop Cc: Bartlomiej Zolnierkiewicz , linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/3] ide: add "ignore_hpa" module parameter Message-ID: <20090525233643.0a47e950@lxorguk.ukuu.org.uk> In-Reply-To: <200905260027.39330.elendil@planet.nl> References: <200905252344.11826.bzolnier@gmail.com> <200905260027.39330.elendil@planet.nl> X-Mailer: Claws Mail 3.7.0 (GTK+ 2.14.7; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > It's also not obvious (at least not to a dumb user like me) that "ignore > HPA limit" is equivalent to "preserving the Host Protected Area" as the > commit commit says. It isn't - its the exact reverse. Ignoring the HPA limit tells the kernel to ignore the system BIOS and firmware set defaults and to stomp the whole disk regardless. On a modern system thats almost always a really bad idea. Unfortunately on ancient boxes with disk jumpers set to lie about the disk size (32GB clipping etc) its the right thing. Having the same parameter in both stacks seems a good idea but really we need Tejun's patch exposing the values and then to propogate the hpa ignore into sysfs and trigger a revalidate of the disk if you change it. Libata has all the framework for that ready just needing the final bits. I don't see anything problematic in old IDE also having that interface.