From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754156AbaIKV7c (ORCPT ); Thu, 11 Sep 2014 17:59:32 -0400 Received: from www.linutronix.de ([62.245.132.108]:43783 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752907AbaIKV7a (ORCPT ); Thu, 11 Sep 2014 17:59:30 -0400 Date: Thu, 11 Sep 2014 23:59:25 +0200 (CEST) From: Thomas Gleixner To: Andy Shevchenko cc: Jiang Liu , Mika Westerberg , Linux Kernel Mailing List , x86@kernel.org Subject: Re: Ask help about pre_init_apic_IRQ0() In-Reply-To: <1410448503.7023.27.camel@linux.intel.com> Message-ID: References: <54116106.5090904@linux.intel.com> <1410444181.7023.25.camel@linux.intel.com> <1410448503.7023.27.camel@linux.intel.com> User-Agent: Alpine 2.10 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 11 Sep 2014, Andy Shevchenko wrote: > 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. That was with the patch applied, right? What happens if you undo the patch and add the command line options? Thanks, tglx