From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH] Initialize PIIX3 IDE channels as "enabled" Date: Tue, 13 Mar 2007 10:01:16 +0200 Message-ID: <45F65A4C.1030009@qumranet.com> References: <45F57685.BA47.005A.0@novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org To: Gregory Haskins Return-path: In-reply-to: <45F57685.BA47.005A.0-Et1tbQHTxzrQT0dZR+AlfA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org Gregory Haskins wrote: > This patch initializes the PIIX3 IDE controllers IDE channels as enabled. They were previously unconfigured by QEMU. > > IDE devices have been broken on our local lab systems since the introduction of QEMU 0.9.0 (KVM-14). Tracing the Linux driver for PIIX3 initialization revealed that the "enabled" bits (bit 7 in the PCI-CONFIG space at address 0x41 and 0x43, port 0 and 1 respectively) were not set. In a bare-metal system, it would typically be the role of the BIOS to enable something like this, so this solution may be a hack. I speculate that the real bug may be something introduced into Bochs about the same time as the 0.9.0 deployment, but I have not investigated this. Nonetheless, unless there is a specific run-time switch to enable/disable the IDE channels, initializing them in QEMU vs Bochs is probably 6 of one, half dozen of the other. > > Is the bug present in stock qemu-0.9.0? I'm no acpi expert, but this may be related to our acpi breakage. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic. ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV