From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Andries E. Brouwer" Subject: Re: ide boot failure 2.6.36/2.6.28 - 2.6.27 works Date: Sat, 20 Nov 2010 04:28:33 +0100 Message-ID: <20101120032828.GA14693@iq> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from hera.cwi.nl ([192.16.191.8]:52742 "EHLO hera.cwi.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932127Ab0KTD2r (ORCPT ); Fri, 19 Nov 2010 22:28:47 -0500 Content-Disposition: inline Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org Answering myself (and providing info that can be Googled): > I wanted to boot a recent kernel on an old machine and failed. > The last kernel that worked was 2.6.27. > What goes wrong is that the disks are no longer detected on 2.6.28. A typical error would be Cannot open root device 342 or unknown block (3,66) Reading the code shows that the default probing is no longer done. Editing ./drivers/ide/ide-generic.c and changing -static int probe_mask; +static int probe_mask = 3; returns my disks to life, and this old machine boots again. Andries