From mboxrd@z Thu Jan 1 00:00:00 1970 From: Len Brown Subject: Re: [patch 7/7] acpi: remove old blacklist entries Date: Wed, 17 Feb 2010 13:24:58 -0500 (EST) Message-ID: References: <201002022238.o12Mbx54018702@imap1.linux-foundation.org> <20100216154053.GA31195@srcf.ucam.org> <20100217143245.GA18411@srcf.ucam.org> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Return-path: Received: from vms173015pub.verizon.net ([206.46.173.15]:35091 "EHLO vms173015pub.verizon.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750786Ab0BQSZZ (ORCPT ); Wed, 17 Feb 2010 13:25:25 -0500 Received: from localhost.localdomain ([unknown] [74.104.151.18]) by vms173015.mailsrvcs.net (Sun Java(tm) System Messaging Server 7u2-7.02 32bit (built Apr 16 2009)) with ESMTPA id <0KY0000MG0HSB6O2@vms173015.mailsrvcs.net> for linux-acpi@vger.kernel.org; Wed, 17 Feb 2010 12:25:08 -0600 (CST) In-reply-to: <20100217143245.GA18411@srcf.ucam.org> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Matthew Garrett Cc: akpm@linux-foundation.org, linux-acpi@vger.kernel.org, arekm@maven.pl, feng.tang@intel.com, flinco@libero.it, mad_soft@inbox.ru, rjw@sisk.pl On Wed, 17 Feb 2010, Matthew Garrett wrote: > On Tue, Feb 16, 2010 at 09:49:03PM -0500, Len Brown wrote: > > > In the future, I'll consider deleting the "acpi=ht" > > option all together, and the blacklist with it, > > but such changes are always harder than expected. > > We seem to have no good history of where these blacklist entries came > from, and we know that at least one of them is actively harmful. Perhaps > replace them with a debug statement on affected machines telling people > what they need to pass to restore the blacklist behaviour, and to let us > know if it's necessary? Actually, it wasn't actively harmful until we broke "acpi=ht". Indeed, it was actively helpful in pointing out that regression:-) Yes, I think that a warning for a release or so before deleting some of these entries would make sense -- good idea. Re: history... unfortunately old-2.6-bkcvs history is nearly useless, but bkbits still seems to work. It shows I pulled this DMI list from Linux-2.4 to Linux-2.6 on 2003-08-09, and that it originally came from Suse: "pull DMI blacklist from UnitedLinux via 2.4 for disabling ACPI on bad BIOS boxes. This also sets ACPI_BLACKLIST_CUTOFF_YEAR = 2001" http://linux.bkbits.net:8080/linux-2.6.11-stable/arch/i386/kernel/dmi_scan.c?PAGE=diffs&REV=3f35b565a8XFxBnmR2yf-97PQRqW3Q I think that move was a short term good idea, but a long term bad idea. It looks like we have added no forc_acpi_ht entries since 2003, but we have deleted a bunch of them. So it may indeed be time for the force_acpi_ht, and perhaps the "acpi=ht" option to go. The other entries in today's acpi_dmi_table[] are less clear and should probably be modified only with some care... I'll spin a patch for the acpi=ht part. thanks, -Len Brown, Intel Open Source Technology Center