From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752793AbdLSRXp (ORCPT ); Tue, 19 Dec 2017 12:23:45 -0500 Received: from bombadil.infradead.org ([65.50.211.133]:37587 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750844AbdLSRXj (ORCPT ); Tue, 19 Dec 2017 12:23:39 -0500 Date: Tue, 19 Dec 2017 18:23:27 +0100 From: Peter Zijlstra To: Zhang Rui Cc: Thomas Gleixner , LKML , linux-x86 , Len Brown , "Chen, Yu C" Subject: Re: Regression: unable to boot after commit bd9240a18edf ("x86/apic: Add TSC_DEADLINE quirk due to errata") - Surface Pro 4 SKL Message-ID: <20171219172327.bcpss5in2k4346xh@hirez.programming.kicks-ass.net> References: <1511857335.2498.22.camel@intel.com> <1511866741.2441.5.camel@intel.com> <20171128123607.fmgpq76brf6bdkk4@hirez.programming.kicks-ass.net> <1511966690.2750.9.camel@intel.com> <20171218202822.juwyxsd7millme7o@hirez.programming.kicks-ass.net> <1513680504.2569.1.camel@intel.com> <20171219152307.ugmlynst574wsdne@hirez.programming.kicks-ass.net> <1513698161.2745.14.camel@intel.com> <20171219160155.zgu5clv5mj2l4aaj@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20171219160155.zgu5clv5mj2l4aaj@hirez.programming.kicks-ass.net> User-Agent: NeoMutt/20170609 (1.8.3) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Dec 19, 2017 at 05:01:55PM +0100, Peter Zijlstra wrote: > On Tue, Dec 19, 2017 at 11:42:41PM +0800, Zhang Rui wrote: > > On Tue, 2017-12-19 at 16:23 +0100, Peter Zijlstra wrote: > > > > [    0.000000] ACPI: INT_SRC_OVR (bus 0 bus_irq 0 global_irq 2 dfl dfl) > > > [    0.000000] ACPI: IRQ0 used by override. > > > > > > So your ACPI table has an override for IRQ2 and routes it to IRQ0. > > ^ this > > > > The HPET document says: > > > > > >   If the ENABLE_CNF bit and the LEG_RT_CNF bit are both set, then the > > >   interrupts will be routed as follows: > > > > > >     Timer 0 will be routed to IRQ0 in Non-APIC or IRQ2 in the I/O APIC > > > > But AFAICS, the HPET emulated timer interrupts goes to IRQ0 > > Right, so see that ACPI override, that routes I/O APIC IRQ2 to IRQ0, or > it _should_. > > Clearly something is messed up here.. but I've no idea what. That whole > IRQ routing stuff is confusing. Does this help? diff --git a/arch/x86/kernel/time.c b/arch/x86/kernel/time.c index 749d189f8cd4..45675072771c 100644 --- a/arch/x86/kernel/time.c +++ b/arch/x86/kernel/time.c @@ -69,8 +69,6 @@ static struct irqaction irq0 = { static void __init setup_default_timer_irq(void) { - if (!nr_legacy_irqs()) - return; setup_irq(0, &irq0); }