Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751915AbbLDOGM (ORCPT ); Fri, 4 Dec 2015 09:06:12 -0500 Received: from smtp02.citrix.com ([66.165.176.63]:32183 "EHLO SMTP02.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751027AbbLDOGK (ORCPT ); Fri, 4 Dec 2015 09:06:10 -0500 X-IronPort-AV: E=Sophos;i="5.20,380,1444694400"; d="scan'208";a="322681312" Message-ID: <56619DCE.3050900@citrix.com> Date: Fri, 4 Dec 2015 14:06:06 +0000 From: David Vrabel User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Icedove/31.8.0 MIME-Version: 1.0 To: David Vrabel , CC: , Ingo Molnar , "H. Peter Anvin" , , Thomas Gleixner , Boris Ostrovsky , "Vitaly Kuznetsov" Subject: Re: [Xen-devel] [PATCHv1] x86: rtc_cmos platform device requires legacy irqs References: <1449139404-25101-1-git-send-email-david.vrabel@citrix.com> In-Reply-To: <1449139404-25101-1-git-send-email-david.vrabel@citrix.com> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-DLP: MIA2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2178 Lines: 69 On 03/12/15 10:43, David Vrabel wrote: > Adding the rtc platform device when there are no legacy irqs (no > legacy PIC) causes a conflict with other devices that end up using the > same irq number. An alternative is to remove the rtc_cmos platform device in Xen PV guests. Any preference on how this regression should be fixed? David 8<-------------------------- x86: Xen PV guests don't have the rtc_cmos platform device Adding the rtc platform device in a Xen PV guests causes an IRQ conflict because these guests do not have a legacy PIC. In a single VCPU Xen PV guest we should have: /proc/interrupts: CPU0 0: 4934 xen-percpu-virq timer0 1: 0 xen-percpu-ipi spinlock0 2: 0 xen-percpu-ipi resched0 3: 0 xen-percpu-ipi callfunc0 4: 0 xen-percpu-virq debug0 5: 0 xen-percpu-ipi callfuncsingle0 6: 0 xen-percpu-ipi irqwork0 7: 321 xen-dyn-event xenbus 8: 90 xen-dyn-event hvc_console ... But hvc_console cannot get its interrupt because it is already in use by rtc0 and the console does not work. genirq: Flags mismatch irq 8. 00000000 (hvc_console) vs. 00000000 (rtc0) So don't add the rtc_cmos device in Xen PV guests. Reported-by: Sander Eikelenboom Signed-off-by: David Vrabel Tested-by: Sander Eikelenboom --- arch/x86/kernel/rtc.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/x86/kernel/rtc.c b/arch/x86/kernel/rtc.c index cd96852..7b190b8 100644 --- a/arch/x86/kernel/rtc.c +++ b/arch/x86/kernel/rtc.c @@ -200,6 +200,9 @@ static __init int add_rtc_cmos(void) } #endif + if (xen_pv_domain()) + return -ENODEV; + platform_device_register(&rtc_device); dev_info(&rtc_device.dev, "registered platform RTC device (no PNP device found)\n"); -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/