Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757001AbYFYCmP (ORCPT ); Tue, 24 Jun 2008 22:42:15 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753233AbYFYCl6 (ORCPT ); Tue, 24 Jun 2008 22:41:58 -0400 Received: from vms046pub.verizon.net ([206.46.252.46]:39057 "EHLO vms046pub.verizon.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751793AbYFYCl5 (ORCPT ); Tue, 24 Jun 2008 22:41:57 -0400 Date: Tue, 24 Jun 2008 22:41:27 -0400 (EDT) From: Len Brown Subject: Re: [PATCH] ACPI: don't walk tables if ACPI was disabled In-reply-to: <20080624114139.GC21890@elte.hu> X-X-Sender: lenb@localhost.localdomain To: Ingo Molnar Cc: Vegard Nossum , linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, Zhao Yakui , "Rafael J. Wysocki" , Alexey Starikovskiy , Yinghai Lu , Bjorn Helgaas Message-id: MIME-version: 1.0 Content-type: TEXT/PLAIN; charset=US-ASCII References: <20080620135639.GA5073@damson.getinternet.no> <19f34abd0806201340t502ce471n578dd2498a5f1992@mail.gmail.com> <19f34abd0806201427h740ca3e7gc2f01c7e34616fd4@mail.gmail.com> <19f34abd0806210119o64a1c9ban78710651a01530cf@mail.gmail.com> <20080624114139.GC21890@elte.hu> User-Agent: Alpine 1.10 (LFD 962 2008-03-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2169 Lines: 57 On Tue, 24 Jun 2008, Ingo Molnar wrote: > * Vegard Nossum wrote: > > > On Fri, Jun 20, 2008 at 11:27 PM, Vegard Nossum wrote: > > > So I guess this function, pnpbios_init() needs the check as well. In > > > fact, it has this: > > > > > > #ifdef CONFIG_PNPACPI > > > if (!acpi_disabled && !pnpacpi_disabled) { > > > pnpbios_disabled = 1; > > > printk(KERN_INFO "PnPBIOS: Disabled by ACPI PNP\n"); > > > return -ENODEV; > > > } > > > #endif /* CONFIG_ACPI */ > > > > > > ...I guess that should be changed to say if (acpi_disabled || > > > pnpacpi_disabled)? Or... I don't understand the purpose of the > > > original test. But it seems to be there since the beginning of time > > > (or, well, v2.6.12-rc2). > > > > Nope. I found the introduction of the change in the historical git repository: > > > > commit 4723ebe898a32262ed49fe677897ccea47e72ff4 > > Author: Adam Belay > > Date: Sun Oct 24 15:07:32 2004 -0400 > > > > [PNPBIOS] disable if ACPI is active > > > > As further ACPI pnp functionaility is implemented it is no longer > > safe to run ACPI and PNPBIOS concurrently. > > > > We therefore take the following approach: > > - attempt to enable ACPI support > > - if ACPI fails (blacklist etc.) enable pnpbios support > > - if ACPI support is not compiled in the kernel enable pnpbios support > > > > Signed-off-by: Adam Belay > > > > and now I understand the purpose of the check; pnpbios does not depend > > on ACPI; ACPI/pnpacpi is incompatible with pnpbios. > > wow, rather old bug - i guess lockdep made it more visible. No, that commit was not a bug, it was correct, and still is, for pnpACPI and pnpBIOS must be mutually exclusive. The thing that changed was the RTC specific code. -Len -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/