From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sun, 15 Sep 2002 21:23:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sun, 15 Sep 2002 21:23:59 -0400 Received: from harpo.it.uu.se ([130.238.12.34]:41378 "EHLO harpo.it.uu.se") by vger.kernel.org with ESMTP id ; Sun, 15 Sep 2002 21:23:58 -0400 Date: Mon, 16 Sep 2002 03:28:53 +0200 (MET DST) From: Mikael Pettersson Message-Id: <200209160128.DAA04146@harpo.it.uu.se> To: arysin@myrealbox.com, linux-kernel@vger.kernel.org Subject: Re: turning off APIC Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 15 Sep 2002 14:28:44 +0300, Andriy Rysin wrote: >If APIC is compiled in the kernel (wich is the case with most >distributions) when I start kernel with "noapic" option, APIC is getting >enabled anyway and only later gets disabled. This causes problems on >some VAIO notebooks - it seems like BIOS gets confused if APIC was >turned on (particularly on my laptop when I try to reboot from Linux it >hangs saying that thera problems with keyboard). That would be much >better to have an option to turn it off in the boot options and not to >recompile the kernel. Could somebody comment this please? >Please CC me on this email address. Which APIC? local or I/O? Please be specific. "noapic" does not and never has had anything to do with the local APIC, only the I/O APIC. There is currently no kernel option for preventing the local APIC from being enabled if the kernel was built with local APIC support. You have four options: 1. Recompile with CONFIG_SMP=n and CONFIG_X86_LOCAL_APIC=n. 2. Run dmidecode on your Vaio, dig out the identification strings, and add them to arch/i386/kernel/dmi_scan.c's local APIC blacklist. 3. Add a __setup in arch/i386/kernel/apic.c after the declaration for dont_enable_local_apic, which sets it to 1. 4. Tell Sony to fix the Vaio's BIOS. /Mikael