From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Sender: rtc-linux@googlegroups.com Received: from mail.free-electrons.com (down.free-electrons.com. [37.187.137.238]) by gmr-mx.google.com with ESMTP id o85si1124799wme.0.2016.07.19.07.29.14 for ; Tue, 19 Jul 2016 07:29:14 -0700 (PDT) Date: Tue, 19 Jul 2016 16:29:07 +0200 From: Alexandre Belloni To: Pratyush Anand Cc: Alessandro Zummo , rtc-linux@googlegroups.com, open list , Prarit Bhargava , RuiRui Yang , Thomas Gleixner , mingo@kernel.org Subject: [rtc-linux] Re: [PATCH RFC 0/2] rtc-cmos: Workaround unwanted interrupt generation Message-ID: <20160719142907.GG7132@piout.net> References: <20160627044907.GA29870@dhcppc9> <20160704161948.GB11075@dhcppc9> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 In-Reply-To: Reply-To: rtc-linux@googlegroups.com List-ID: List-Post: , List-Help: , List-Archive: , List-Unsubscribe: , Hi, On 18/07/2016 at 17:17:44 +0530, Pratyush Anand wrote : > Hi RTC-Maintainers, > > > On Mon, Jul 4, 2016 at 9:49 PM, Pratyush Anand wrote: > > On 27/06/2016:10:19:07 AM, Pratyush Anand wrote: > >> On 21/06/2016:10:25:34 AM, Pratyush Anand wrote: > >> > We have observed on few machines with rtc-cmos device that > >> > hpet_rtc_interrupt() is called before cmos_do_probe() could call > >> > hpet_rtc_timer_init(). It has not been observed during normal boot/reboot > >> > of machines. It *sometime* happens when system is booted with kdump > >> > secondary kernel. So, neither hpet_default_delta nor hpet_t1_cmp is > >> > initialized by the time interrupt is raised in the given situation. > >> > Therefore while loop of hpet_cnt_ahead() in hpet_rtc_timer_reinit() never > >> > completes. This leads to "NMI watchdog: Watchdog detected hard LOCKUP on > >> > cpu 0". > >> > > >> > I am still clueless, how can an interrupt be raised before RTC is enabled. > >> > But i do not have any idea about this device, so I am putting this patch as > >> > RFC to get feedback from hpet/rtc-cmos developer. I am sure there would be > >> > some better solution than this. > >> > >> Do you think that if I improve commit log of patches as pointed by Thomas and > >> send a formal version of these patches, then they should acceptable to upstream? > > > > A gentle reminder for your comment/feedback :-) > > Please let me know how to make progress on this. If you think, there > could be some better way to handle this issue then please let me know. > If you need any more data then also please let me know. > Well, the change is x86 specific and I don't know much about HPET so until you get an ack from the x86 maintainers, I guess I can't help much. -- Alexandre Belloni, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com -- You received this message because you are subscribed to "rtc-linux". Membership options at http://groups.google.com/group/rtc-linux . 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From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753938AbcGSO3V (ORCPT ); Tue, 19 Jul 2016 10:29:21 -0400 Received: from down.free-electrons.com ([37.187.137.238]:49743 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753654AbcGSO3Q (ORCPT ); Tue, 19 Jul 2016 10:29:16 -0400 Date: Tue, 19 Jul 2016 16:29:07 +0200 From: Alexandre Belloni To: Pratyush Anand Cc: Alessandro Zummo , rtc-linux@googlegroups.com, open list , Prarit Bhargava , RuiRui Yang , Thomas Gleixner , mingo@kernel.org Subject: Re: [PATCH RFC 0/2] rtc-cmos: Workaround unwanted interrupt generation Message-ID: <20160719142907.GG7132@piout.net> References: <20160627044907.GA29870@dhcppc9> <20160704161948.GB11075@dhcppc9> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.6.0 (2016-04-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On 18/07/2016 at 17:17:44 +0530, Pratyush Anand wrote : > Hi RTC-Maintainers, > > > On Mon, Jul 4, 2016 at 9:49 PM, Pratyush Anand wrote: > > On 27/06/2016:10:19:07 AM, Pratyush Anand wrote: > >> On 21/06/2016:10:25:34 AM, Pratyush Anand wrote: > >> > We have observed on few machines with rtc-cmos device that > >> > hpet_rtc_interrupt() is called before cmos_do_probe() could call > >> > hpet_rtc_timer_init(). It has not been observed during normal boot/reboot > >> > of machines. It *sometime* happens when system is booted with kdump > >> > secondary kernel. So, neither hpet_default_delta nor hpet_t1_cmp is > >> > initialized by the time interrupt is raised in the given situation. > >> > Therefore while loop of hpet_cnt_ahead() in hpet_rtc_timer_reinit() never > >> > completes. This leads to "NMI watchdog: Watchdog detected hard LOCKUP on > >> > cpu 0". > >> > > >> > I am still clueless, how can an interrupt be raised before RTC is enabled. > >> > But i do not have any idea about this device, so I am putting this patch as > >> > RFC to get feedback from hpet/rtc-cmos developer. I am sure there would be > >> > some better solution than this. > >> > >> Do you think that if I improve commit log of patches as pointed by Thomas and > >> send a formal version of these patches, then they should acceptable to upstream? > > > > A gentle reminder for your comment/feedback :-) > > Please let me know how to make progress on this. If you think, there > could be some better way to handle this issue then please let me know. > If you need any more data then also please let me know. > Well, the change is x86 specific and I don't know much about HPET so until you get an ack from the x86 maintainers, I guess I can't help much. -- Alexandre Belloni, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com