Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 7 Jan 2002 08:17:11 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 7 Jan 2002 08:17:01 -0500 Received: from zikova.cvut.cz ([147.32.235.100]:33540 "EHLO zikova.cvut.cz") by vger.kernel.org with ESMTP id ; Mon, 7 Jan 2002 08:16:53 -0500 From: "Petr Vandrovec" Organization: CC CTU Prague To: Chris Wedgwood Date: Mon, 7 Jan 2002 14:16:28 +0100 MIME-Version: 1.0 Content-type: text/plain; charset=US-ASCII Content-transfer-encoding: 7BIT Subject: Re: "APIC error on CPUx" - what does this mean? CC: swsnyder@home.com, Linux Kernel Mailing List , alan@lxorguk.ukuu.org.uk X-mailer: Pegasus Mail v3.40 Message-ID: Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On 8 Jan 02 at 2:08, Chris Wedgwood wrote: > On Mon, Jan 07, 2002 at 01:29:42PM +0100, Petr Vandrovec wrote: > > They are spurious IRQ 7, just message is printed only once during > kernel lifetime... I have about three spurious IRQ 7 per each 1000 > interrupts delivered to CPU. It is on A7V (Via KT133). > > Any idea _why_ these occur though? It seems some mainboards produce a > plethora of these whilst others never produce these... Nope. Probably when CPU is in local APIC mode, it acknowledges interrupts to chipset with different timming, and from time to time CPU still sees IRQ pending, so it asks for vector, but as chipset has no interrupt pending, it answers with IRQ7. I did no analysis to find whether IRQ7 happens directly when we send confirmation to 8259, or whether it happens due to some noise on IRQ line. AFAIK it happens only on VIA based boards, and only if (AMD) CPU is using APIC. Best regards, Petr Vandrovec vandrove@vc.cvut.cz - 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/