Return-path: Received: from dgate1.fujitsu-siemens.com ([217.115.66.35]) by canuck.infradead.org with esmtps (Exim 4.63 #1 (Red Hat Linux)) id 1IIhRw-00012o-Dt for kexec@lists.infradead.org; Wed, 08 Aug 2007 05:03:30 -0400 Message-ID: <46B986D5.2010407@fujitsu-siemens.com> Date: Wed, 08 Aug 2007 11:03:17 +0200 From: Martin Wilck MIME-Version: 1.0 Subject: Re: PATCH/RFC: [kdump] fix APIC shutdown sequence References: <46B73955.2080007@fujitsu-siemens.com> <20070807142928.GA18839@in.ibm.com> <46B8AECA.7050908@fujitsu-siemens.com> In-Reply-To: List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: kexec-bounces@lists.infradead.org Errors-To: kexec-bounces+dwmw2=infradead.org+dwmw2=infradead.org@lists.infradead.org To: "Eric W. Biederman" Cc: Haren Myneni , "vgoyal@in.ibm.com" , "kexec@lists.infradead.org" , "linux-kernel@vger.kernel.org" Hello Eric, > How bad is it if you just run with irqpoll in the kdump kernel? > If running with irqpoll is usable that is probably preferable > to putting in a hardware work around we can survive without. Yes, I tried that. No effect. > Have you done any looking at moving where the kernel initalizes > io_apics? One of the todo items on the path is to leave > io_apic mode enabled and just startup the kernel in io_apic > mode. I have tried to recover from the "IRR set" situation in several ways by changing setup_IO_APIC_irq(). But I haven't found a way to recover from this situation once disable_IO_APIC() had been called. I concluded thatthe sequence of events "send INT message - never receive EOI - disable IO-APIC pin" messes up the IO-APIC (at least this specific one in the PCIEx-PCI bridge of the ICH7). The current state of affairs is that the only thing that "worked" was to re-enable irqs. > When doing that a version of your work around (if needed) > would certainly be reasonable. > My general concern is that the trickier we get in the code > running in the crashed kernel the less reliable the entire > process will be. That's certainly correct. I am grateful for all hints that simplify my patch. Thanks, Martin -- Martin Wilck PRIMERGY System Software Engineer FSC IP ESP DE6 Fujitsu Siemens Computers GmbH Heinz-Nixdorf-Ring 1 33106 Paderborn Germany Tel: ++49 5251 8 15113 Fax: ++49 5251 8 20409 Email: mailto:martin.wilck@fujitsu-siemens.com Internet: http://www.fujitsu-siemens.com Company Details: http://www.fujitsu-siemens.com/imprint.html _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec