Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1423054AbXBHOlM (ORCPT ); Thu, 8 Feb 2007 09:41:12 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1423046AbXBHOlL (ORCPT ); Thu, 8 Feb 2007 09:41:11 -0500 Received: from nf-out-0910.google.com ([64.233.182.190]:4877 "EHLO nf-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1423054AbXBHOlK (ORCPT ); Thu, 8 Feb 2007 09:41:10 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=sp0wzgviiHkA7pGqlIIPe1eDDV/CcV9jMmXSDjx5cQwNntYs1eyjP66tX+vViSt9DKA4xgg5slhAyPsgb7n70sGqqiu3KevCZqzF62kvKHPfJVWRhWaJ6peBvywrN0HSC3MoUJOqATBhq+ZfOqDIBZeWi1MPGNP49oVCYL5GdX4= Message-ID: Date: Thu, 8 Feb 2007 09:41:03 -0500 From: "Dmitry Torokhov" To: "Andi Kleen" Subject: Re: [PATCH 9/11] Panic delay fix Cc: "Zachary Amsden" , "Linux Kernel Mailing List" , "Andrew Morton" , "Rusty Russell" , "Jeremy Fitzhardinge" , "Chris Wright" In-Reply-To: <20070208133321.GA36397@muc.de> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <200702060353.l163rUmj000771@zach-dev.vmware.com> <20070206122729.GC47229@muc.de> <45C8FA2D.6010706@vmware.com> <45CA535D.1080700@vmware.com> <20070208082443.GA9928@muc.de> <45CAE87E.8070502@vmware.com> <20070208133321.GA36397@muc.de> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2044 Lines: 53 On 8 Feb 2007 14:33:21 +0100, Andi Kleen wrote: > On Thu, Feb 08, 2007 at 01:08:14AM -0800, Zachary Amsden wrote: > > Andi Kleen wrote: > > >On Wed, Feb 07, 2007 at 02:31:57PM -0800, Zachary Amsden wrote: > > > > > >>Dmitry Torokhov wrote: > > >> > > >>>I am confused - does i8042 talk to a virtual or real hardware here? In > > >>>any case I think you need to fix kernel/panic.c to have proper > > >>>(m)delay, not mess with i8042. > > >>> > > >>I think I need to fix both of them actually. This is virtual hardware, > > >>but when you grab focus on a VM, the virtual hardware gets reflected to > > >>the actual physical keyboard. Driving physical hardware that fast is bad. > > >> > > > > > >??? > > > > > >Surely the physical keyboard is always handled by the host kernel? > > >I hope you're not saying it's trying to access the io ports directly? > > > > > > > No, not that. But the virtual keyboard I/O gets processed and converted > > to physical keyboard I/O when a keyboard is attached to a VM. The > > You mean the commands to change the keyboard LEDs? > > > result is that the virtual keyboard spinning out of control causes the > > physical keyboard to receive the same commands, far too rapidly. > > Hmm i would expect the host kernel keyboard driver to throttle these. > I'm pretty sure the Linux one does the necessary mdelays at least. There is no throttling, we will switch leds as fast as keyboard controller will allow us (not that I consider it a bad thing). > > > So the keyboard blinks out of control and acts as if possessed by demons. > > Still sounds weird. > The problem is that panic blink routine expects to be called with 1ms frequency. If mdelay in kernel/panic.c is changed to noop then i8042 will try to blink as fast as it possibly can. -- Dmitry - 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/