From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756517AbaIKPRE (ORCPT ); Thu, 11 Sep 2014 11:17:04 -0400 Received: from mga09.intel.com ([134.134.136.24]:54520 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750852AbaIKPRC (ORCPT ); Thu, 11 Sep 2014 11:17:02 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.04,506,1406617200"; d="scan'208";a="476899144" Message-ID: <1410448503.7023.27.camel@linux.intel.com> Subject: Re: Ask help about pre_init_apic_IRQ0() From: Andy Shevchenko To: Thomas Gleixner Cc: Jiang Liu , Mika Westerberg , Linux Kernel Mailing List , x86@kernel.org Date: Thu, 11 Sep 2014 18:15:03 +0300 In-Reply-To: References: <54116106.5090904@linux.intel.com> <1410444181.7023.25.camel@linux.intel.com> Organization: Intel Finland Oy Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.12.5-1+b1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2014-09-11 at 16:35 +0200, Thomas Gleixner wrote: > On Thu, 11 Sep 2014, Andy Shevchenko wrote: > > On Thu, 2014-09-11 at 14:58 +0200, Thomas Gleixner wrote: > > [] > > > > > According to the MID code the apbt horror is only used for moorestown. > > > Medfield and later use the local apic timer without the apbt nonsense. > > > > > > The best thing we can do is to drop moorestown support and get rid of > > > that apbt nonsense alltogether. > > > > Alan Cox removed Moorestown (as a platform) support in 2012 IIRC. > > So, AFAIK you may safely remove those leftovers. > > Good. > > > > I don't think anyone deeply cares about it not being supported from > > > 3.18 on. The number of devices which sport a moorestown should be > > > pretty limited and the only relevant use case of those is to act as a > > > pocket heater with short battery life time. Its pretty pointless to > > > update kernels on pocket heaters except for bragging reasons. > > > > > > If someone at Intel really thinks that we need to keep moorestown > > > alive for other than documentary and sentimental reasons, then we can > > > move the apbt setup to x86_init.timers.setup_percpu_clockev(). At that > > > point the IOAPIC is setup already, so it should just work. Untested > > > patch below. > > > > Suddenly I have one priority work to do and my Medfield tablet doesn't > > boot by some reason. I would try to test it as soon as I can. > > The patch wont make a difference, except you add With patch nothing happened indeed. > x86_intel_mid_timer=apbt_only [ 0.116839] BUG: unable to handle kernel NULL pointer dereference at 0000003a [ 0.123803] IP: [] setup_irq+0xf/0x4d ... > or > x86_intel_mid_timer=lapic_and_apbt [ 0.116858] BUG: unable to handle kernel NULL pointer dereference at 0000003a [ 0.123820] IP: [] setup_irq+0xf/0x4d ... > > on the kernel commandline. But even w/o that patch I doubt that > anything post moorestown even has that apbt trainwreck implemented. If > I'm right then the commandline option will prevent the thing to boot > at all, which is an even better reason to remove that crap > alltogether. See above. > > Thanks, > > tglx > > > > -- Andy Shevchenko Intel Finland Oy