From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756423Ab0LHT3M (ORCPT ); Wed, 8 Dec 2010 14:29:12 -0500 Received: from mx1.redhat.com ([209.132.183.28]:41141 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751733Ab0LHT3K (ORCPT ); Wed, 8 Dec 2010 14:29:10 -0500 Date: Wed, 8 Dec 2010 14:01:58 -0500 From: Don Zickus To: Yinghai Lu Cc: Peter Zijlstra , "Eric W. Biederman" , Vivek Goyal , Ingo Molnar , Jason Wessel , "linux-kernel@vger.kernel.org" , Haren Myneni Subject: Re: perf hw in kexeced kernel broken in tip Message-ID: <20101208190158.GA8565@redhat.com> References: <1291234036.32004.2008.camel@laptop> <20101202052321.GH18100@redhat.com> <1291275270.4023.20.camel@twins> <20101202161502.GL18100@redhat.com> <1291764620.2032.1293.camel@laptop> <20101208140103.GM21786@redhat.com> <1291818005.28378.38.camel@laptop> <1291820356.28378.83.camel@laptop> <4CFFD1C2.1080108@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4CFFD1C2.1080108@kernel.org> User-Agent: Mutt/1.5.20 (2009-08-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Dec 08, 2010 at 10:43:14AM -0800, Yinghai Lu wrote: > > can you add sth force_... in command line to take over ownership of perf from BIOS or previous kernel ? > > then still can use perf etc after we kexec from RHEL or SLES kernel to later kernel ( from 2.6.37) My understand is that you can't because the BIOS is actively using it behind the scenes of the kernel (well during an SMI). I have a machine where I tried to force take it but it still stopped triggering interrupts. Cheers, Don